Update mirror.yml

Specify exact versions for actions/cache  and actions/checkout to get more frequent update on this repository

.github/workflows/mirror.yml

@@ -25,7 +25,7 @@ jobs:
           sudo apt-get install git-svn --no-install-recommends
 
       - name: checkout mirror config branch
-        uses: actions/checkout@v3
+        uses: actions/checkout@v3.0.2
 
       - name: Get current date as seconds
         id: get-date
@@ -45,7 +45,7 @@ jobs:
       - name: Cache runners svn-2-git-fhem mirror directory  
         # Some room for improvement because we create a new cache on every run where a new ref is fetched, this isn't very nice, normaly weneed only the last one and it takes 7 days until they are deleted
         id: cache-fhem
-        uses: actions/cache@v3
+        uses: actions/cache@v3.0.8
         with:
           path: ./src/fhem-mirror/.git
           key: ${{ runner.os }}-fhemsvndir-${{ steps.get-date.outputs.timestamp }}