Add a troubleshooting note when EasyCLA is blocked. (#2364)

From graphql/ai-wg#99 (comment)

Author: martinbonnin

src/pages/community/contribute/project-meetings.mdx

@@ -128,6 +128,11 @@ You can read about the agreement, including details about whether to sign as an
 
 ![EasyCLA recognizes the signed CLA](./images/development/Step2-5.png)
 
+<Callout type="info">
+  There should be only one email associated to your commit. If the CLA check fails, double check this is the case by using this command: `git show -s --format='Author: %an <%ae>%nCommitter: %cn <%ce>' HEAD`
+</Callout>
+
+
 ### Add yourself to the list of attendees
 
 1. Find your [chosen working group above](#graphql-working-group--tsc-meeting) and find its next agenda by browsing to agendas -> year -> month in the central pane of the GitHub webpage