Do not use deprecated macos-10.15 runner (#6724)

.github/workflows/fleetctl-preview.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         # Doesn't work on Windows because Linux Docker containers are not supported.
-        os: [ubuntu-20.04, ubuntu-18.04, macos-10.15, macos-11]
+        os: [ubuntu-20.04, ubuntu-18.04, macos-11, macos-12]
     runs-on: ${{ matrix.os }}
     steps:
     - name: Install Docker

.github/workflows/goreleaser-snapshot-fleet.yaml

@@ -9,7 +9,9 @@ jobs:
   publish:
     # Only run it when the push is to the fleetdm/fleet repo. Otherwise the secrets for pushing to
     # Docker will not be available.
-    if: github.repository_owner == 'fleetdm' 
+    #
+    # Also not run if author is dependabot (it doesn't have access to Github secrets).
+    if: ${{ (github.repository == 'fleetdm/fleet') && (github.actor != 'dependabot[bot]') }}
     runs-on: ubuntu-latest
     environment: Docker Hub
     steps: