Update deploy-branches.yml

Author: dm0n3y

.github/workflows/deploy-branches.yml

@@ -16,14 +16,17 @@ jobs:
           path: source
       - name: Add name of current branch to environment as BRANCH_NAME
         uses: nelonoel/[email protected]
-      - name: Clear opam cache
-        run: rm -rf /home/runner/.opam/        
       - name: Retrieve build environment if cached # STEP 2
         id: opam-cache
         uses: actions/cache@v4
         with:
           path: '/home/runner/.opam/'
           key: ${{ runner.os }}-modules-${{ hashFiles('./source/opam.export') }}
+      - name: Add opam repository archive
+        run: |
+          eval $(opam env)
+          export OPAMYES=1
+          opam repo add archive git+https://github.com/ocaml/opam-repository-archive
       - name: Install dependencies and build tylr # STEP 3
         run: |
           sudo apt --assume-yes install opam