minor #1221 Update .gitattributes to remove tests from "dist" (barryvdh)

This PR was merged into the 6.2-dev branch.

Discussion
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Update .gitattributes to remove tests from "dist"

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Doc update?   | no
| BC breaks?    | no
| Deprecations? | no
| Fixed tickets | #268 #804 #839
| License       | MIT

This was proposed many times before, but considering symfony/symfony#33579 is now merged, I propose this again. I refer to that issue as for the reasoning, as it applies here also.

Commits
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e5e0ce0 Update .gitattributes

.gitattributes

@@ -5,5 +5,7 @@
 *.priv -crlf
 *.txt -crlf
 
-# ignore /notes in the git-generated distributed .zip archive
+# ignore directories in the git-generated distributed .zip archive
 /doc/notes export-ignore
+/tests export-ignore
+/phpunit.xml.dist export-ignore