Harden GitHub Actions workflows

- Pin every action ref to a full-length commit SHA with a trailing
  version comment, so floating tags like @v4 can't be re-pointed at
  malicious code.
- Bump outdated actions/checkout@v1 to @v4.3.1 (where present).
- Tag-triggered workflows now check out with fetch-depth: 1 and
  fetch-tags: true so the tag ref is available downstream.
- release-tracker.yml grants contents: write at the job level so the
  default GITHUB_TOKEN can push commits/tags back to the repo.

Signed-off-by: Tamal Saha <tamal@appscode.com>

Author: tamalsaha

.github/workflows/ci.yml

@@ -19,12 +19,12 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Set up Go 1.25
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5.6.0
         with:
           go-version: '1.25'
         id: go
 
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Run checks
         run: |