Update github-api to 1.125 (#2717)

Fixed file names passed to syntax highlighter in diff view (#2716)

Solve repository deletion error on Windows (#2711) ...

- Added function to delete given folder recursively.
- Used the function for deleting the folder, while deleting repository.

fixes #2628

Revert workaround for timestamp issue in war file creation (#2714)

Update github-api to 1.124

Update oauth2-oidc-sdk to 9.2.3

Update sbt-twirl to 1.5.1

Update org.eclipse.jgit.archive, ... to 5.11.0.202103091610-r

add explicit types for implicit val ...

prepare Scala 3

use slash syntax

Update thumbnailator to 0.4.14

Update sbt to 1.4.9

avoid do-while ...

prepare Scala 3

https://dotty.epfl.ch/docs/reference/dropped-features/do-while.html

Update sbt to 1.4.8

Update oauth2-oidc-sdk to 9.2.2

Update HikariCP to 4.0.3

Update json4s-jackson to 3.6.11 (#2699)

Update auto_update.md

Update build.md

Update jetty-continuation, jetty-http, ... to 9.4.38.v20210224

Update github-api to 1.123

Update oauth2-oidc-sdk to 9.2.1

ignore jetty 11.x and 10.x updates

Update testcontainers-scala to 0.39.3 (#2695)

Update README.md (#2694) ...

## Developer information is hard to find

I've been looking for instructions on how to build gitbucket a couple of times, and I've never found them until takzoe pointed me towards `doc/build.md`. After knowing about this, I read through the readme once again, looking for such a link, and then I've found it as the last sentence within a section named `Features`.

What I've been looking for:
 - either a file named `INSTALL.md`, `BUILD.md` in `/`
 - or a section (or a link) in the main readme

I've put the link to `doc/readme.md` into a separate section "Building and Development" and added a short summary. I'm not so sure about the order of the new section and "Plugins".

Update testcontainers-scala to 0.39.2 (#2693)

Update scala-library to 2.13.5

Update oauth2-oidc-sdk to 9.2

Update jetty-continuation, jetty-http, ... to 9.4.37.v20210219

Update mockito-core to 3.8.0