Fix mock repo injection: use --shell instead of --copyin

.forgejo/workflows/build-rpms.yml

@@ -50,14 +50,13 @@ jobs:
 
       - name: Build RPM with mock
         run: |
-          curl -fsSL https://pc-rytteren.dk/forge/api/packages/anders/rpm.repo \
-            -o /tmp/sonicde.repo
           mock \
             --root alma+epel-10-x86_64 \
             --init
+          REPO_CONTENT=$(curl -fsSL https://pc-rytteren.dk/forge/api/packages/anders/rpm.repo)
           mock \
             --root alma+epel-10-x86_64 \
-            --copyin /tmp/sonicde.repo /etc/yum.repos.d/sonicde.repo
+            --shell "echo '${REPO_CONTENT}' > /etc/yum.repos.d/sonicde.repo"
           mock \
             --root alma+epel-10-x86_64 \
             --resultdir "${HOME}/mock-results" \