gitlab/issue_templates: add Change_Kernel_Config.md (MR 5549)

Related: https://postmarketos.org/kconfig-adjust-multiple

[ci:skip-build]: already built successfully in CI

.gitlab/issue_templates/Change_Kernel_Config.md

@@ -0,0 +1,31 @@
+<!-- Use this template to kick off the discussion for changing one or more
+     related kernel config options.
+-->
+
+### Read the fine manual, please :)
+
+- [ ] I have read https://postmarketos.org/kconfig-adjust-multiple
+
+### What benefit does the change have?
+
+### Which option(s) would you like to change?
+
+<!-- Make sure to specify if you would like to enable/disable/set a value. -->
+
+### Did you already test that this works as expected?
+
+<!-- Not required, but recommended. If you did test it, please list which
+     device you have tested it with. -->
+
+### For which kernel configs would you do the change?
+
+<!-- If it makes sense, we encourage to adjust all kernels used by devices in
+     the main and community categories, so devices behave consistently. -->
+
+- [ ] all in main and community
+- [ ] certain SoC(s):
+- [ ] other (please specify):
+
+
+<!-- leave this, so it applies the correct label in gitlab -->
+/change-kernel-config