[nrf noup] scripts: ci: check_compliance: Exclude release docs

Ddds the NCS release notes folder to the exclusion list for
undefined Kconfigs so that old Kconfigs can be used e.g. for old
release notes

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

scripts/ci/check_compliance.py

@@ -1156,6 +1156,7 @@ def check_no_undef_outside_kconfig(self, kconf):
         grep_stdout = git("grep", "--line-number", "-I", "--null",
                           "--perl-regexp", regex, "--", ":!/doc/releases",
                           ":!/doc/security/vulnerabilities.rst",
+                          ":!/doc/nrf/releases_and_maturity",
                           cwd=GIT_TOP)
 
         # splitlines() supports various line terminators