🔧 Pin mattermost-notify action to its v2.1.0 commit SHA

The notify steps referenced mattermost/action-mattermost-notify@master, a
mutable branch that runs in CI with access to the MATTERMOST_WEBHOOK_URL
secret. Pinning to the immutable commit of the latest release (v2.1.0,
ae31bb6) keeps the exact reviewed code from executing, per GitHub third-party
action hardening guidance, while staying easy to bump.

.github/workflows/build-bundle.yml

@@ -85,7 +85,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/build-docker-devenv.yml

@@ -40,7 +40,7 @@ jobs:
           cache-to: type=registry,ref=${{ env.DOCKER_IMAGE }}:buildcache,mode=max
 
       - name: Notify Mattermost
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/build-docker.yml

@@ -175,7 +175,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/build-tag.yml

@@ -29,7 +29,7 @@ jobs:
 
     steps:
       - name: Notify Mattermost
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/plugins-deploy-api-doc.yml

@@ -131,7 +131,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/plugins-deploy-package.yml

@@ -114,7 +114,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/plugins-deploy-styles-doc.yml

@@ -129,7 +129,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd

.github/workflows/release.yml

@@ -103,7 +103,7 @@ jobs:
 
       - name: Notify Mattermost
         if: failure()
-        uses: mattermost/action-mattermost-notify@master
+        uses: mattermost/action-mattermost-notify@ae31bb6f9e26a54336e79696f108a2c91cf55b4e # v2.1.0
         with:
           MATTERMOST_WEBHOOK_URL: ${{ secrets.MATTERMOST_WEBHOOK }}
           MATTERMOST_CHANNEL: bot-alerts-cicd