Update tags for renovatebot (slsa-framework#622)

* Update pre-submit.units.yml

Signed-off-by: laurentsimon <[email protected]>

* Update pre-submit.units.yml

Signed-off-by: laurentsimon <[email protected]>

Author: laurentsimon

.github/workflows/pre-submit.units.yml

@@ -65,12 +65,12 @@ jobs:
     if: ${{ always() }}
     steps:
       - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # v2.3.4
+        uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579 # tag=v2.3.4
         with:
           path: generator
 
       - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # v2.3.4
+        uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579 # tag=v2.3.4
         with:
           path: verifier
           repository: slsa-framework/slsa-verifier