Trigger actions on v2 (#2982)

### Description

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### Drive-by changes

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### Related issues

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- Fixes #[issue number here]
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### Backward compatibility

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### Testing

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.github/workflows/monorepo-docker.yml

@@ -1,7 +1,7 @@
 name: Build and Push Monorepo Image to GCR
 on:
   push:
-    branches: [main]
+    branches: [v2]
     tags:
       - '**'
   pull_request:

.github/workflows/rust-docker.yml

@@ -1,7 +1,7 @@
 name: Build and Push Agent Image to GCR
 on:
   push:
-    branches: [main]
+    branches: [v2]
     tags:
       - '**'
   pull_request:

.github/workflows/rust-skipped.yml

@@ -3,7 +3,7 @@ name: rust
 
 on:
   pull_request:
-    branches: [main]
+    branches: [v2]
     paths-ignore:
       - 'rust/**'
 

.github/workflows/rust.yml

@@ -2,7 +2,7 @@ name: rust
 
 on:
   push:
-    branches: [main]
+    branches: [v2]
   pull_request:
     paths:
       - 'rust/**'