workflows: build: Ensure rootfs is present for shim-v2 build

Let's ensure that we get the already built rootfs tarball from previous
steps of the action at the time we're building the shim-v2.

The reason we do that is because the rootfs binary tarballs has a
root_hash.txt file that contains the information needed the shim-v2
build scripts to add the measured rootfs arguments to the shim-v2
configuration files.

Signed-off-by: Fabiano Fidêncio <fabiano@fidencio.org>

.github/workflows/build-kata-static-tarball-amd64.yaml

@@ -224,9 +224,17 @@ jobs:
         env:
           TARGET_BRANCH: ${{ inputs.target-branch }}
 
+      - name: get-artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: kata-artifacts-amd64-*${{ inputs.tarball-suffix }}
+          path: kata-artifacts
+          merge-multiple: true
+
       - name: Build shim-v2
         id: build
         run: |
+          ./tests/gha-adjust-to-use-prebuilt-components.sh kata-artifacts "${KATA_ASSET}"
           make "${KATA_ASSET}-tarball"
           build_dir=$(readlink -f build)
           # store-artifact does not work with symlink

.github/workflows/build-kata-static-tarball-arm64.yaml

@@ -164,8 +164,16 @@ jobs:
         env:
           TARGET_BRANCH: ${{ inputs.target-branch }}
 
+      - name: get-artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: kata-artifacts-arm64-*${{ inputs.tarball-suffix }}
+          path: kata-artifacts
+          merge-multiple: true
+
       - name: Build shim-v2
         run: |
+          ./tests/gha-adjust-to-use-prebuilt-components.sh kata-artifacts "${KATA_ASSET}"
           make "${KATA_ASSET}-tarball"
           build_dir=$(readlink -f build)
           # store-artifact does not work with symlink

.github/workflows/build-kata-static-tarball-ppc64le.yaml

@@ -177,8 +177,16 @@ jobs:
         env:
           TARGET_BRANCH: ${{ inputs.target-branch }}
 
+      - name: get-artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: kata-artifacts-ppc64le-*${{ inputs.tarball-suffix }}
+          path: kata-artifacts
+          merge-multiple: true
+
       - name: Build shim-v2
         run: |
+          ./tests/gha-adjust-to-use-prebuilt-components.sh kata-artifacts "${KATA_ASSET}"
           make "${KATA_ASSET}-tarball"
           build_dir=$(readlink -f build)
           # store-artifact does not work with symlink

.github/workflows/build-kata-static-tarball-s390x.yaml

@@ -240,9 +240,17 @@ jobs:
         env:
           TARGET_BRANCH: ${{ inputs.target-branch }}
 
+      - name: get-artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: kata-artifacts-s390x-*${{ inputs.tarball-suffix }}
+          path: kata-artifacts
+          merge-multiple: true
+
       - name: Build shim-v2
         id: build
         run: |
+          ./tests/gha-adjust-to-use-prebuilt-components.sh kata-artifacts "${KATA_ASSET}"
           make "${KATA_ASSET}-tarball"
           build_dir=$(readlink -f build)
           # store-artifact does not work with symlink