pgsql: Fix .gitignore for src/interfaces/libpq-oauth.

Fix .gitignore for src/interfaces/libpq-oauth.

This missed files created when running the oauth tests.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/66fa3b5eef6e4764a3beb097ecc9e04b6d956bc9

Modified Files
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src/interfaces/libpq-oauth/.gitignore | 3 +++
1 file changed, 3 insertions(+)