ci: Various CI improvements

.github/workflows/ci.yaml

@@ -1,6 +1,11 @@
 name: "Rust CI"
 on:
   pull_request:
+    paths:
+      - "crates/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - ".github/workflows/ci.yaml"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}

.github/workflows/pr-title.yaml

@@ -8,18 +8,19 @@ on:
       - synchronize
 
 jobs:
-  lint:
+  lint-pr-title:
+    name: Check PR title
     runs-on: ubuntu-latest
     permissions:
       statuses: write
       pull-requests: write
     steps:
-      - uses: amannn/action-semantic-pull-request@v5
+      - uses: amannn/action-semantic-pull-request@0723387faaf9b38adef4775cd42cfd5155ed6017 # v5
         id: lint_pr_title
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-      - uses: marocchino/sticky-pull-request-comment@v2
+      - uses: marocchino/sticky-pull-request-comment@331f8f5b4215f0445d3c07b4967662a32a2d3e31 # v2
         # When the previous steps fails, the workflow would stop. By adding this
         # condition you can continue the execution with the populated error message.
         if: always() && (steps.lint_pr_title.outputs.error_message != null)
@@ -43,7 +44,7 @@ jobs:
 
       # Delete a previous comment when the issue has been resolved
       - if: ${{ steps.lint_pr_title.outputs.error_message == null }}
-        uses: marocchino/sticky-pull-request-comment@v2
+        uses: marocchino/sticky-pull-request-comment@331f8f5b4215f0445d3c07b4967662a32a2d3e31 # v2
         with:   
           header: pr-title-lint-error
           delete: true

.github/workflows/test-gpu.yaml

@@ -2,9 +2,11 @@ name: Test on GPU
 
 on:
   pull_request:
-    branches: [ main ]
-  push:
-    branches: [ main ]
+    paths:
+      - "crates/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - ".github/workflows/test-gpu.yaml"
 
 jobs:
   zksync-crypto-gpu-build: