Pin Slack GitHub actions to major version v2 (#803)

Author: zliang-akamai

.github/workflows/e2e-suite.yml

@@ -294,7 +294,7 @@ jobs:
     steps:
       - name: Notify Slack
         id: main_message
-        uses: slackapi/slack-github-action@v2.1.0
+        uses: slackapi/slack-github-action@v2
         with:
           method: chat.postMessage
           token: ${{ secrets.SLACK_BOT_TOKEN }}
@@ -326,7 +326,7 @@ jobs:
 
       - name: Test summary thread
         if: success()
-        uses: slackapi/slack-github-action@v2.1.0
+        uses: slackapi/slack-github-action@v2
         with:
           method: chat.postMessage
           token: ${{ secrets.SLACK_BOT_TOKEN }}

.github/workflows/nightly-smoke-tests.yml

@@ -46,7 +46,7 @@ jobs:
 
       - name: Notify Slack
         if: always() && github.repository == 'linode/linode-cli' # Run even if integration tests fail and only on main repository
-        uses: slackapi/slack-github-action@v2.1.0
+        uses: slackapi/slack-github-action@v2
         with:
           method: chat.postMessage
           token: ${{ secrets.SLACK_BOT_TOKEN }}

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - name: Notify Slack - Main Message
         id: main_message
-        uses: slackapi/slack-github-action@v2.1.0
+        uses: slackapi/slack-github-action@v2
         with:
           method: chat.postMessage
           token: ${{ secrets.SLACK_BOT_TOKEN }}