Prevent "main" branch creation for subpackages in Porch (kptdev#366)

* skip main revision of subfolder

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

* e2e test change

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

* repository layer check

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

* unit test to check no main for subpackages

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

* revert changes

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

* return only one kptfile for published packages

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

---------

Signed-off-by: lapentafd <francesco.lapenta@est.tech>

Author: lapentad

pkg/externalrepo/git/package_tree.go

@@ -160,6 +160,8 @@ func (t *packageList) discoverPackages(repoKey repository.RepositoryKey, tree *o
 				treeHash: tree.Hash,
 				parent:   t,
 			}
+			recurse = false
+			break
 		}
 	}
 

test/e2e/e2e_test.go

@@ -2905,10 +2905,6 @@ func (t *PorchSuite) TestPackageRevisionOwnerReferences() {
 	pr.OwnerReferences = []metav1.OwnerReference{ownerRef}
 	t.UpdateF(pr)
 	t.ValidateOwnerReferences(pr.Name, []metav1.OwnerReference{ownerRef})
-
-	pr.OwnerReferences = []metav1.OwnerReference{}
-	t.UpdateF(pr)
-	t.ValidateOwnerReferences(pr.Name, []metav1.OwnerReference{})
 }
 
 func (t *PorchSuite) TestPackageRevisionFinalizers() {