feat: update steamuser and steampass in common.cfg

The commit updates the code to properly insert the `steamuser` and `steampass` values in the `common.cfg` file. The previous code was not correctly formatting the values, which caused issues with server installation. This change ensures that the values are properly formatted using double quotes for `steamuser` and single quotes for `steampass`.

.github/workflows/update-check.yml

@@ -33,7 +33,7 @@ jobs:
 
       - name: Insert steamuser
         if: matrix.shortname == 'jk2'
-        run: echo "steamuser="${STEAMCMD_USER}\nsteampass='${STEAMCMD_PASS}'" lgsm/config-lgsm/${{ matrix.shortname }}server/common.cfg
+        run: echo -e "steamuser=\"${STEAMCMD_USER}\"\nsteampass='${STEAMCMD_PASS}'" lgsm/config-lgsm/${{ matrix.shortname }}server/common.cfg
 
       - name: Install server
         run: LGSM_GITHUBBRANCH="${GITHUB_REF#refs/heads/}" ./${{ matrix.shortname }}server auto-install