Move the CI from Travis to GitHub Actions (#17)

This change makes the CI to be run by GitHub Actions instead of Travis.
This is a lot less flaky and a tad bit faster.

This also automates the release process and builds the artifacts so that
I don't have to run a weird script on my machine every time.

.github/workflows/ci.yml

@@ -0,0 +1,67 @@
+name: CI
+
+on:
+  pull_request: {}
+  push:
+    branches:
+      - master
+
+jobs:
+
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        go:
+          - 1.13
+          - 1.14
+    name: Go ${{ matrix.go }}
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go }}
+        id: go
+
+      - name: Install golint
+        run: go install golang.org/x/lint/golint
+
+      - name: Install git2go
+        run: |
+          export GOPATH="$(go env GOPATH)"
+          go mod edit -replace "github.com/lhchavez/git2go/v29=${GOPATH}/src/github.com/lhchavez/git2go"
+          git clone --recurse-submodules https://github.com/lhchavez/git2go "${GOPATH}/src/github.com/lhchavez/git2go"
+          go get -d github.com/lhchavez/git2go/v29
+          (cd "${GOPATH}/src/github.com/lhchavez/git2go/" && ./script/build-libgit2-static.sh)
+
+      - name: Lint
+        run: golint -set_exit_status ./...
+
+      - name: Get dependencies
+        run: go get -tags=static -t -v ./...
+
+      - name: Vet
+        run: go vet -tags=static -v ./...
+
+      - name: Test
+        run: go test -tags=static -v  -race -coverprofile=coverage.txt -covermode=atomic ./...
+
+      - name: Ensure formatting
+        run: |
+          if [[ $(git ls-tree -r HEAD^{tree} . --full-name --name-only | \
+                  grep '\.go$' | \
+                  xargs -n 1 gofmt -d | \
+                  wc -c) -ne 0 \
+          ]]; then
+            echo "please run gofmt on all the files"
+            exit 1
+          fi
+
+      - name: Upload code coverage
+        run: bash <(curl -s https://codecov.io/bash)

.github/workflows/release.yml

@@ -0,0 +1,96 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - v*
+
+jobs:
+
+  release:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.13
+        id: go
+
+      - name: Install git2go
+        run: |
+          export GOPATH="$(go env GOPATH)"
+          go mod edit -replace "github.com/lhchavez/git2go/v29=${GOPATH}/src/github.com/lhchavez/git2go"
+          git clone --recurse-submodules https://github.com/lhchavez/git2go "${GOPATH}/src/github.com/lhchavez/git2go"
+          go get -d github.com/lhchavez/git2go/v29
+          (cd "${GOPATH}/src/github.com/lhchavez/git2go/" && ./script/build-libgit2-static.sh)
+
+      - name: Get dependencies
+        run: go get -tags=static -t -v ./...
+
+      - name: Bump version and push tag
+        id: bump-version
+        uses: anothrNick/github-tag-action@c170e78287f338a4af0dc49e033e50e5a072d82b
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          WITH_V: true
+          DEFAULT_BUMP: patch
+          INITIAL_VERSION: 1.0.0
+
+      - name: Build
+        run: |
+          mkdir -p artifacts/backend/usr/bin/
+          go build -o artifacts/backend/usr/bin/omegaup-grader \
+            -ldflags "-X main.ProgramVersion=${{ steps.bump-version.outputs.tag }}" \
+            -tags=static \
+            github.com/omegaup/quark/cmd/omegaup-grader
+          go build -o artifacts/backend/usr/bin/omegaup-broadcaster \
+            -ldflags "-X main.ProgramVersion=${{ steps.bump-version.outputs.tag }}" \
+            -tags=static \
+            github.com/omegaup/quark/cmd/omegaup-broadcaster
+
+          mkdir -p artifacts/runner/usr/bin/
+          go build -o artifacts/runner/usr/bin/omegaup-runner \
+            -ldflags "-X main.ProgramVersion=${{ steps.bump-version.outputs.tag }}" \
+            -tags=static \
+            github.com/omegaup/quark/cmd/omegaup-runner
+
+      - name: Package
+        run: |
+          tar -cJf omegaup-backend.tar.xz --owner=root:0 --group=root:0 -C artifacts/backend/ .
+          tar -cJf omegaup-runner.tar.xz --owner=root:0 --group=root:0 -C artifacts/runner/ .
+
+      - name: Create Release
+        id: create-release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ steps.bump-version.outputs.tag }}
+          release_name: ${{ steps.bump-version.outputs.tag }}
+          draft: false
+          prerelease: false
+
+      - name: Upload omegaup-backend.tar.xz Release Asset
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create-release.outputs.upload_url }}
+          asset_path: ./omegaup-backend.tar.xz
+          asset_name: omegaup-backend.tar.xz
+          asset_content_type: application/octet-stream
+
+      - name: Upload omegaup-runner.tar.xz Release Asset
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create-release.outputs.upload_url }}
+          asset_path: ./omegaup-runner.tar.xz
+          asset_name: omegaup-runner.tar.xz
+          asset_content_type: application/octet-stream