Fix: add missing test fail template (#155)

### Description

Add missing template used in the CI.

.github/TEST_FAIL_TEMPLATE.md

@@ -0,0 +1,12 @@
+---
+title: "{{ env.TITLE }}"
+labels: [bug]
+---
+The {{ workflow }} workflow failed on {{ date | date("YYYY-MM-DD HH:mm") }} UTC
+
+The most recent failing test was on {{ env.PLATFORM }} py{{ env.PYTHON }}
+with commit: {{ sha }}
+
+Full run: https://github.com/{{ repo }}/actions/runs/{{ env.RUN_ID }}
+
+(This post will be updated if another test fails, as long as this issue remains open.)