[#20] Use selfhosted actions mirror

TrueCloudLab/frostfs-infra#152

Signed-off-by: Vitaliy Potyarkin <v.potyarkin@yadro.com>

.forgejo/workflows/updatechecker.yml

@@ -5,7 +5,7 @@ jobs:
   checkupdates:
     runs-on: docker
     steps:
-      - uses: https://code.forgejo.org/actions/checkout@v3
+      - uses: actions/checkout@v3
       - run: make update
       - run: |
           git config user.name "Snegurochka"