Add gi-docgen as a subproject

While we're developing gi-docgen it's better to have it as part of our
build.

diff --git a/subprojects/gi-docgen.wrap b/subprojects/gi-docgen.wrap
new file mode 100644 (file)
index 0000000..e9c78c1
--- /dev/null
+++ b/subprojects/gi-docgen.wrap
@@ -0,0 +1,6 @@
+[wrap-git]
+directory=gi-docgen
+url=https://gitlab.gnome.org/ebassi/gi-docgen.git
+push-url=ssh://git@gitlab.gnome.org:ebassi/gi-docgen.git
+revision=main
+depth=1