fixup! Adding interop tests

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from #22726)

.github/workflows/interop-tests.yml

@@ -1,3 +1,8 @@
+# Notes:
+# /__w/openssl is the path that github bind-mounts into the container so the ci
+# filesystem for this job can be reached.  Please note that any changes made to
+# this job involving file system paths should be made prefixed with, or relative
+# to that directory
 name: Interoperability tests with GnuTLS and NSS
 on:
   schedule: