ci: use actions/cache for restore/save cache, gh for deleting cache

`actions/cache` does not allow for updating the cache, so we need to
delete the old cache and save a new one in order to keep reusing the
key.

.github/workflows/build.yml

@@ -94,24 +94,36 @@ jobs:
           restore-keys: |
             depends-sources-
 
-      - name: Cache dependencies
-        uses: actions/cache@v4
+      - name: Restore dependencies cache
+        id: cache-restore-deps
+        uses: actions/cache/restore@v4
         with:
           path: |
             depends/built
+            depends/${{ matrix.host }}
           key: ${{ runner.os }}-depends-${{ matrix.depends_name }}-${{ hashFiles('depends/packages/*') }}
-          restore-keys: |
-            ${{ runner.os }}-depends-${{ matrix.depends_name }}-${{ hashFiles('depends/packages/*') }}
-            ${{ runner.os }}-depends-${{ matrix.depends_name }}
 
       - name: Build dependencies
         run: env HOST=${{ matrix.host }} ${{ matrix.dep_opts }} make -j$(nproc) -C depends
 
-      - name: Upload built depends
-        uses: actions/upload-artifact@v4
+      - name: Delete dependencies cache
+        id: cache-delete-deps
+        if: ${{ steps.cache-restore-deps.outputs.cache-hit }}
+        continue-on-error: true
+        run: |
+          gh extension install actions/gh-actions-cache
+          gh actions-cache delete "${{ steps.cache-restore-deps.outputs.cache-primary-key }}" --confirm
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Save dependencies cache
+        id: cache-save-deps
+        uses: actions/cache/save@v4
         with:
-          name: depends-${{ matrix.depends_name }}
-          path: depends/${{ matrix.host }}
+          path: |
+            depends/built
+            depends/${{ matrix.host }}
+          key: ${{ steps.cache-restore-deps.outputs.cache-primary-key }}
 
   build:
     name: ${{ matrix.build_target }}
@@ -157,11 +169,13 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.sha }}
 
-      - name: Download built depends
-        uses: actions/download-artifact@v4
+      - name: Restore dependencies cache
+        uses: actions/cache/restore@v4
         with:
-          name: depends-${{ matrix.depends_name }}
-          path: depends/${{ matrix.host }}
+          path: |
+            depends/built
+            depends/${{ matrix.host }}
+          key: ${{ runner.os }}-depends-${{ matrix.depends_name }}-${{ hashFiles('depends/packages/*') }}
 
       - name: Determine PR Base SHA
         id: vars