patch 9.0.1752: CI: Coveralls is no longer used

Problem: CI: Coveralls is no longer used
Solution: Remove .coveralls.yml

Coveralls is no longer used, we ditched using it in patch v9.0.1547,
commit 12eb0f4ec5a9d9899d09691f944e4fbfdf4318fd issue #12389

So let's remove the .coveralls.yml file, it does not seem useful
anymore.

closes: #12851

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 262131c..e2059c8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1752,
+/**/
     1751,
 /**/
     1750,