[chore] Replace usage of gh actions with pinned versions (#12629)

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

.github/workflows/builder-snapshot.yaml

@@ -23,7 +23,7 @@ jobs:
           path: .core
 
       - name: Pull the latest releases repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           path: opentelemetry-collector-releases
           repository: open-telemetry/opentelemetry-collector-releases

.github/workflows/contrib-tests.yml

@@ -28,7 +28,7 @@ jobs:
           contrib_path=/tmp/opentelemetry-collector-contrib
           git clone --depth=1 https://github.com/open-telemetry/opentelemetry-collector-contrib.git $contrib_path
           make CONTRIB_PATH=$contrib_path prepare-contrib
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@4cec3d8aa04e39d1a68397de0c4cd6fb9dce8ec1 # v4.6.1
         with:
           name: contrib
           path: /tmp/opentelemetry-collector-contrib/
@@ -59,7 +59,7 @@ jobs:
       - name: Checkout Repo
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Download contrib
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@cc203385981b70ca67e1cc392babf9cc229d5806 # v4.1.9
         with:
           name: contrib
           path: /tmp/contrib