Add issue template for revdep check failures

.github/ISSUE_TEMPLATE/revdep_check_failure.yml

@@ -0,0 +1,74 @@
+name: Revdep check failure
+description: Report a reverse dependency (revdep) check failure that should be fixed before next CRAN release
+labels: ["revdep"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this template to report a new revdep check failure found via
+        [revdep checks](https://github.com/Rdatatable/data.table/wiki/Revdep-checks).
+        Please verify the failure is real before filing; see checklist on that page.
+
+  - type: input
+    id: package
+    attributes:
+      label: Affected package
+      description: Link to package dev on github.
+      placeholder: e.g. https://github.com/NorskRegnesentral/shapr
+    validations:
+      required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Problem description
+      description: |
+        Brief description of the check failure. Include what kind of failure
+        it is (ERROR, WARNING, NOTE) and which check stage fails
+        (tests, examples, vignettes, etc.).
+      placeholder: revdep shapr has new test failures.
+    validations:
+      required: true
+
+  - type: textarea
+    id: check-output
+    attributes:
+      label: Failing check output
+      description: |
+        Paste the relevant `R CMD check` output showing the failure.
+        The output can be found in the
+        [Monsoon results](https://rcdata.nau.edu/genomic-ml/data.table-revdeps/analyze/)
+        or from a local revdep check.
+      render: text
+    validations:
+      required: true
+
+  - type: input
+    id: first-bad-commit
+    attributes:
+      label: First bad commit/PR
+      description: |
+        Link to the commit or PR identified by `git bisect` as the
+        first bad commit (from the `first.bad.commit` column in the
+        Monsoon significant differences table).
+      placeholder: "https://github.com/Rdatatable/data.table/pull/1234"
+    validations:
+      required: true
+
+  - type: textarea
+    id: mre
+    attributes:
+      label: Minimal reproducible example
+      description: |
+        Optional. A minimal example reproducing the failure outside
+        the revdep package. Useful as a potential data.table test case.
+      render: r
+
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional context
+      description: |
+        Any other relevant information: @mentions of the commit/PR
+        author(s), links to Monsoon result pages, whether the fix
+        should come from data.table or from the revdep package, etc.