{Misc.} Trim trailing whitespace in .github/pull_request_template.md (#15850)
{Misc.} Trim trailing whitespace in .github/pull_request_template.md (#15850)


yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli