Add Brew installation

In addition to the Brew installation notes, the `release-work-after`
script will automate some release routines.

.workflows/release-work-after

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# update Brew formulae
+TAG=$(git describe)
+COMMIT=$(git log --pretty=%H -1)
+
+if type brew >/dev/null 2>&1 ; then
+    info-text "Updating Homebrew formulae..."
+    brew bump-formula-pr --no-audit --tag=${TAG} --revision=${COMMIT} aws-creds
+else
+    error-text "brew binary is not available."
+    error-text "Please make a manual formulae update."
+    cat <<MESSAGE
+Instructions:
+
+    open       https://github.com/bees-hive/homebrew-hive/blob/main/Formula/aws-creds.rb#L4
+    update
+        git tag:     ${TAG}
+        git commit:  ${COMMIT}
+MESSAGE
+fi
+# add GitHub release
+open https://github.com/bees-hive/aws-creds/releases/new

README.md

@@ -22,6 +22,8 @@ requested commands.
 The latest version can be installed using the following command:
 `curl -sSL https://raw.githubusercontent.com/bees-hive/aws-creds/main/install.sh | bash`
 
+For Brew users, just run `brew install bees-hive/hive/aws-creds`.
+
 ## Getting Started
 
 ### AWS IAM Identity Center (AWS SSO)