[buildbot] buildmaster: add some OpenWrt branding

[LEDE Commits]

ynezz pushed a commit to buildbot.git, branch master:
https://git.openwrt.org/8060fb27302ed986d3a108f63ae8fdeb8e6df9d8

commit 8060fb27302ed986d3a108f63ae8fdeb8e6df9d8
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Wed Mar 17 10:28:39 2021 +0100

    buildmaster: add some OpenWrt branding
    
     Welcome to OpenWrt buildbot
    
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 docker/buildmaster/Dockerfile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docker/buildmaster/Dockerfile b/docker/buildmaster/Dockerfile
index 1cf4d56..6ddc99d 100644
--- a/docker/buildmaster/Dockerfile
+++ b/docker/buildmaster/Dockerfile
@@ -36,6 +36,10 @@ RUN \
 		"buildbot-worker==$BUILDBOT_VERSION" \
 		pyOpenSSL \
 		service_identity
+RUN \
+	sed -i \
+	's/Welcome to buildbot/Welcome to OpenWrt buildbot/' \
+	/usr/local/lib/python*/dist-packages/buildbot_www/static/scripts.js
 
 ENV LANG=en_US.utf8