[buildbot] Bump to version 3.0.0

[LEDE Commits]

ynezz pushed a commit to buildbot.git, branch master:
https://git.openwrt.org/950c4858d660038ad47901159dbe1ee70236d1d2

commit 950c4858d660038ad47901159dbe1ee70236d1d2
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Tue Mar 9 20:32:15 2021 +0100

    Bump to version 3.0.0
    
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index df2d17b..fdc3237 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,5 +1,5 @@
 variables:
-  BUILDBOT_VERSION: 2.10.1
+  BUILDBOT_VERSION: 3.0.0
 
 include:
   - local: .gitlab/docker.yml