[gtk-doc] Add sanity.sh to EXTRA_DIST.

[Stefan Sauer <stefkost src gnome org>]

commit 44a4d36e67d00618937afda90382b6983c0edea7
Author: Stefan Sauer <ensonic users sf net>
Date:   Tue Oct 16 21:27:22 2018 +0200

    Add sanity.sh to EXTRA_DIST.
    
    Fixes #54

 tests/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3be6ce0..cbd7402 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -25,7 +25,7 @@ PY_LOG_COMPILER = $(PYTHON)
 
 endif
 
-EXTRA_DIST = gtkdoctest.sh $(TESTS)
+EXTRA_DIST = gtkdoctest.sh sanity.sh $(TESTS)
 
 # run any given test by running make <test>.check
 %.check: %