feat(resourcename): use `Ancestor` function

[glimchb]

see https://github.com/einride/aip-go/blob/ee11a619585d66f42ea91f28d0f42eb4534ea16c/resourcename/ancestor.go#L4

example

			actual, ok := Ancestor(tt.input, tt.pattern)

			input:      "//foo.example.com/foo/1/bar/2",
			pattern:    "foo/{foo}",
			expected:   "//foo.example.com/foo/1",
or

			input:      "foo/1/bar/2",
			pattern:    "foo/{foo}",
			expected:   "foo/1",