Update .github/PULL_REQUEST_TEMPLATE

Co-authored-by: Alex Bozarth <ajbozart@us.ibm.com>
Signed-off-by: Alan Chin <akchin@us.ibm.com>

.github/PULL_REQUEST_TEMPLATE

@@ -24,7 +24,7 @@ If possible, please consider writing useful notes for better and faster reviews
 Please make sure to add some test cases that check the changes thoroughly
 including negative and positive cases, if possible.
 
-If changes was tested in a way different from regular unit tests, please clarify how you tested step by step,
+If changes were tested in a way different from regular unit tests, please clarify how you tested step by step,
 ideally copy and paste-able, so that other reviewers can test and check, and descendants can verify in the future.
 
 If tests were not added, please describe why they were not added e.g. documentation only, GH workflow updates, etc.