[buildbot] Create README.md

[LEDE Commits]

ynezz pushed a commit to buildbot.git, branch master:
https://git.openwrt.org/ab755145a42781ec37c4820f758c1c66c365d7a5

commit ab755145a42781ec37c4820f758c1c66c365d7a5
Author: Petr Štetiar <ynezz at true.cz>
AuthorDate: Mon May 15 08:08:42 2023 +0200

    Create README.md
    
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/README.md b/README.md
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+# OpenWrt buildbot configuration
+
+This repository provides containers used for building OpenWrt at https://buildbot.openwrt.org