Update .clang-tidy to not warn trailing return type

Summary:
This is primarily an update which disables the
`modernize-use-trailing-return-type` suggestion introduced in
clang-tidy-9. Old clang-tidy versions should ignore removed checks which
don't exist in the first place, so this should change should be
compatible with any version.

Reviewers: mferencevic, ipaljak

Reviewed By: mferencevic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2511

.clang-tidy

@@ -41,6 +41,7 @@ Checks: '*,
          -modernize-pass-by-value,
          -modernize-use-equals-default,
          -modernize-use-nodiscard,
+         -modernize-use-trailing-return-type,
          -performance-unnecessary-value-param,
          -readability-braces-around-statements,
          -readability-else-after-return,