patman: Add a Series-patchwork-url option

Add a commit tag to allow the Patchwork URL to be specified in a commit.
This can be handy for when you submit code to multiple projects but don't
want to use the -p option.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/README b/tools/patman/README
index 639c994..6b80663 100644
--- a/tools/patman/README
+++ b/tools/patman/README
@@ -208,6 +208,12 @@
 	branch against patchwork to see what new reviews your series has
 	collected ('patman status').
 
+Series-patchwork-url: url
+	This allows specifying the Patchwork URL for a branch. This overrides
+	both the setting files and the command-line argument. The URL should
+	include the protocol and web site, with no trailing slash, for example
+	'https://patchwork.ozlabs.org/project'
+
 Cover-letter:
 This is the patch set title
 blah blah