ci: pin upstream.yml actions to full commit SHAs

Signed-off-by: El Mehdi Abenhazou <[email protected]>

.github/workflows/upstream.yml

@@ -36,7 +36,7 @@ jobs:
     - name: shutdown VM if running
       run: vmshutdown
       working-directory: ${{ runner.temp }}
-    - uses: actions/checkout@main
+    - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # main
     - name: startup VM
       run: vmstartup
       working-directory: ${{ runner.temp }}
@@ -63,7 +63,7 @@ jobs:
       run: vmrun 'for i in /usr/src/regress/usr.bin/ssh/obj/*.log; do echo ====; echo logfile $i; echo =====; cat $i; done'
     - name: save logs
       if: failure()
-      uses: actions/upload-artifact@main
+      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # main
       with:
         name: ${{ matrix.target }}-${{ matrix.config }}-logs
         path: |