Fix export cache issue

Resolve #1551 and #1020.
We are never returning the result of solved operations so Buildkit could not
cache the layer.
This commit implements a simple system to forward operations' result to the
main build to cache it.

Signed-off-by: Vasek - Tom C <tom.chauveau@epitech.eu>

.github/workflows/test-universe.yml

@@ -57,8 +57,5 @@ jobs:
         uses: crazy-max/ghaction-github-runtime@v1
 
       - name: Test
-        env:
-          DAGGER_CACHE_TO: "type=gha,mode=max,scope=test-universe"
-          DAGGER_CACHE_FROM: "type=gha,mode=max,scope=test-universe"
         run: |
           make universe-test