Try to fix codecov config

Apparently they changed YAML parser, and ! now makes it fail

.codecov.yml

@@ -11,9 +11,9 @@ fixes:
 codecov:
   ci:
     # Cygwin fails integration test with --coverage enabled, I don't know why
-    - !appveyor
+    - "!appveyor"
     # FreeBSD doesn't support C++ coverage yet (can't find libprofile_rt.a)
-    - !jenkins.znc.in
+    - "!jenkins.znc.in"
 coverage:
   status:
     project: