Add geco per author's email request

quicklisp · quicklisp · commit b686a46099fc · 2020-11-26T14:30:03.000-05:00
diff --git a/projects/geco/source.txt b/projects/geco/source.txt
@@ -0,0 +1 @@
+git https://github.com/gpwwjr/GECO.git
