Use LLVM head for builds

clangd/actions/pick is currently broken because LLVM no longer has a
branch called master. We didn't have any releases for past 3 weeks, i've
contacted author in
https://github.com/ramasilveyra/last-successful-gh-commit/issues/2.

.github/workflows/periodic.yaml

@@ -21,17 +21,24 @@ jobs:
     name: Create draft release
     runs-on: ubuntu-latest
     steps:
+    - name: Install deps
+      run: |
+        sudo apt-get install jq
     - name: Clone scripts
       uses: actions/checkout@v2
-    - name: Pick last successful commit
-      id: pick
-      uses: clangd/actions/.github/actions/pick@v0.1.0
-      with:
-        repo: llvm/llvm-project
-        token: ${{ secrets.GITHUB_TOKEN }}
+      # Use clangd/actions/pick after
+      # https://github.com/ramasilveyra/last-successful-gh-commit/issues/2 has
+      # been addressed.
+    - name: Get commit hash for LLVM head
+      run: >
+        curl --fail --show-error
+        "-HAuthorization: Bearer ${{ secrets.RELEASE_TOKEN }}"
+        "https://api.github.com/repos/llvm/llvm-project/commits/main" |
+        jq ".sha" -r > commit
     - name: Compute release info
       run: |
-        echo "RELEASE_COMMIT_SHORT=$(printf '%.12s' ${{ steps.pick.outputs.sha }})" >> $GITHUB_ENV
+        echo "RELEASE_COMMIT=$(cat commit)" >> $GITHUB_ENV
+        echo "RELEASE_COMMIT_SHORT=$(printf '%.12s' $(cat commit))" >> $GITHUB_ENV
         echo "RELEASE_DATE=$(date -u +%Y%m%d)" >> $GITHUB_ENV
     - name: Create release
       uses: actions/create-release@master
@@ -43,7 +50,7 @@ jobs:
         body: |
           Unstable snapshot of clangd on ${{ env.RELEASE_DATE }}.
 
-          Built from llvm/llvm-project@${{ steps.pick.outputs.sha }}.
+          Built from llvm/llvm-project@${{ env.RELEASE_COMMIT }}.
         prerelease: true
         # It would be nice to use draft releases, to hide them from users.
         # But drafts don't fire events to trigger the autobuild workflow.