use GITHUB_TOKEN for login to ghcr

Author: hobu

.github/workflows/build.yml

@@ -22,7 +22,7 @@ jobs:
     env:
       PUSH_PACKAGES: ${{ github.repository_owner == 'PDAL' && github.event_name != 'pull_request'}}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
 
@@ -43,7 +43,7 @@ jobs:
         with:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
-          password: ${{ secrets.GHCR_TOKEN }}
+          password: ${{ secrets.GITHUB_TOKEN }}
       - name: Prepare
         id: prep
         run: |