[PATCH i-g-t v1 1/2] CONTRIBUTING: Add subscription and patchwork info

[Kamil Konieczny]

Add guide and link to subscription into mailing list and link
for patchwork.

Signed-off-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
---
 CONTRIBUTING.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 81057a2ad..b571b5e68 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -63,6 +63,13 @@ Sending Patches
 
   on its first invocation.
 
+- If you plan contribute regularly please subscribe to igt-dev mailinglist:
+  https://lists.freedesktop.org/mailman/listinfo/igt-dev
+  When you are not subscribed, please note that your contribution will take
+  more time to reach to mailing list. You could find out if it was delivered or
+  what is a testing status of your patches at patchwork page:
+  https://patchwork.freedesktop.org/project/igt/series/
+
 - Place relevant prefix in subject, for example when your change is in one
   testfile, use its name without '.c' nor '.h' suffix, like:
   tests/simple_test: short description
-- 
2.49.0