Use a directed acyclic graph for CI tests

This allows us to start certains builds (e.g. Windows runtime tests)
without having to wait for all prior builds to finish.

.gitlab/ci/linux.yml

@@ -42,6 +42,9 @@ test:runtime:linux:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:compiler:linux
+    - test:ivm:linux
 release:compiled:linux-gnu:
   image: registry.gitlab.com/inko-lang/development-docker-images:rust-stable
@@ -59,3 +62,5 @@ release:compiled:linux-gnu:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:runtime:linux

.gitlab/ci/macos.yml

@@ -48,6 +48,9 @@ test:runtime:macos:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:compiler:macos
+    - test:ivm:macos
 release:compiled:macos:
   stage: release
@@ -67,3 +70,5 @@ release:compiled:macos:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:runtime:macos

.gitlab/ci/windows.yml

@@ -49,6 +49,9 @@ test:runtime:windows:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:compiler:windows
+    - test:ivm:windows
 release:compiled:windows:
   stage: release
@@ -68,3 +71,5 @@ release:compiled:windows:
     paths:
       - .cargo
       - vm/target
+  needs:
+    - test:runtime:windows