adds flaky test issue template (#13577)

.github/ISSUE_TEMPLATE/flaky_test.md

@@ -0,0 +1,72 @@
+---
+name: Flaky Test ❄
+about: Report a flaky unit or integration test
+title: `TestName` flakiness
+labels: flaky tests
+---
+
+## Before submitting a new issue
+
+Before filing a new issue, search https://github.com/gravitational/teleport/issues?q=is%3Aissue+is%3Aopen+label%3A%22flaky+tests%22 for
+the flaky test's name to see if the same issue has already been reported. If so, double check the `Relevant snippet` to confirm that
+the specific failure is the same. If it is, please react 👍 to this issue (so we can sort issues by reactions). If you have a link to the
+full log of the test run, please add it to the `Link(s) to logs` section below. If instead you've encountered a new failure, edit the issue
+and copy paste in a new `Failure` section below the existing one(s).
+
+If there's no existing issue for this test, continue to file a new one:
+
+1. Change `TestName` in the title to the name of the test that failed.
+2. Use `git blame` to try and figure out who is most responsible for the test, and assign them to this issue.
+3. **Delete this entire section and continue**.
+
+## Failure
+
+#### Link(s) to logs
+
+- Update the link below with the similar link to the logs of the test run that failed, **then delete this line**.
+- https://console.cloud.google.com/cloud-build/builds/f3a2add5-a72a-4332-8f5e-76134492da9d?project=ci-account
+
+#### Relevant snippet
+
+**replace everything below here with your snippet**
+
+Be extra helpful by adding the relevant snippet of the logs that show where the failure takes place.
+See the examples below.
+
+##### `check` style test, ctrl-F for "FAIL:"
+
+```
+FAIL: services_test.go:159: ServicesSuite.TestSemaphoreContention
+
+/workspace/lib/services/suite/suite.go:1222:
+    c.Assert(err, check.IsNil)
+... value *trace.TraceErr =
+ERROR REPORT:
+Original Error: *trace.LimitExceededError too much contention on semaphore connection/alice
+Stack Trace:
+	/workspace/lib/services/local/presence.go:760 github.com/gravitational/teleport/lib/services/local.(*PresenceService).AcquireSemaphore
+	/workspace/lib/services/semaphore.go:245 github.com/gravitational/teleport/lib/services.AcquireSemaphoreLock
+	/workspace/lib/services/suite/suite.go:1221 github.com/gravitational/teleport/lib/services/suite.(*ServicesTestSuite).SemaphoreContention.func1
+	/opt/go/src/runtime/asm_amd64.s:1571 runtime.goexit
+User Message: too much contention on semaphore connection/alice ("too much contention on semaphore connection/alice")
+```
+
+##### `testing` style test, ctrl-F for "Test:"
+
+```
+    tsh_test.go:667:
+        	Error Trace:	tsh_test.go:667
+        	Error:      	Received unexpected error:
+        	            	exit code 1
+        	Test:       	TestSSHAccessRequest
+```
+
+## Update the Flaky Test Tracker meta-issue
+
+After submitting this issue, add a comment to our `Flaky Test Tracker` issue (https://github.com/gravitational/teleport/issues/9492) in the format:
+
+`TestName`: https://github.com/gravitational/teleport/issues/<issue-number>
+
+See https://github.com/gravitational/teleport/issues/9492#issuecomment-1158937319 for an example.
+
+**Delete this section, submit the issue, and add the comment**