clang-tidy: Enable readability-isolate-declaration check

This check detects local variable declarations declaring more than
one variable and tries to refactor the code to one statement per
declaration.

Change-Id: Ie51ae4cbabb0d71e26e8cacd329a0886604395a9
Signed-off-by: Pavithra Barithaya <pavithrabarithaya07@gmail.com>
diff --git a/.clang-tidy b/.clang-tidy
index 3856aa5..51ee20b 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -236,6 +236,7 @@
 readability-deleted-default,
 readability-function-size,
 readability-identifier-naming,
+readability-isolate-declaration,
 readability-make-member-function-const,
 readability-misleading-indentation,
 readability-misplaced-array-index,