Tweaks to format workflow

Author: egil

.github/workflows/main.yml

@@ -124,8 +124,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
         with:
-          fetch-depth: 0
-          ref: ${{ github.head_ref }}
+          ref: ${{ github.event.pull_request.head.sha }}
 
       - uses: actions/setup-dotnet@v1
         with:
@@ -147,7 +146,7 @@ jobs:
           author_name: Github Actions
           author_email: actions@github.com
           message: Automated dotnet-format update
-          ref: ${{ github.head_ref }}
+          ref: ${{ github.event.pull_request.head.sha }}
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
@@ -170,6 +169,7 @@ jobs:
         SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
 
   code-ql:
+    if: github.event_name != 'pull_request'
     runs-on: ubuntu-latest
     steps:
     - name: Checkout repository
@@ -179,11 +179,6 @@ jobs:
         # a pull request then we can checkout the head.
         fetch-depth: 0
 
-      # If this run was triggered by a pull request event, then checkout
-      # the head of the pull request instead of the merge commit.
-    - run: git checkout HEAD^2
-      if: ${{ github.event_name == 'pull_request' }}
-
     - uses: actions/setup-dotnet@v1
       with:
         dotnet-version: '3.1.x'