* Merge branch 'stable-5.2' into stable-5.3

* sshd: don't lock the known_hosts files on reading
* Allow info messages in UsernamePasswordCredentialsProvider
* ssh config: do environment variable replacement
* sshd: implement server-sig-algs SSH extension (client side)

* JGit v5.8.0.202006091008-r

* Remove no longer used API problem filter

* AppServer: Stop using deprecated SslContextFactory constructor
* Enable and fix "Statement unnecessarily nested within else clause" warnings

* Make TestRepository AutoCloseable

* Call AdvertiseRefsHook for protocol v2

* Upgrade spotbugs-maven-plugin to 3.1.9

* Upgrade wagon-ssh to 3.2.0
* Upgrade maven-jxr-plugin to 3.0.0
* Upgrade maven-shade-plugin to 3.2.0
* Upgrade jacoco-maven-plugin to 0.8.2
* Upgrade maven-project-info-reports-plugin to 3.0.0
* Upgrade maven-enforcer-plugin to 3.0.0-M2
* Upgrade maven surefire plugins to 2.22.0
* Ensure same version of maven-surefire-plugin and maven-surefire-report-plugin

* Merge branch 'stable-4.8' into stable-4.9

* Merge branch 'stable-4.9' into stable-4.10

* Nullable: Switch to TYPE_USE
* NonNull: Switch to TYPE_USE
* NonNull: Fix typo in javadoc

* Merge branch 'stable-4.5'

* ReceivePack: integrate push option parsing into recvCommands
* ReceivePack: simplify getPushOptions
* ReceivePack: allow push options to be set

* FS: Remove the gitprefix logic
* SystemReader: Use discoverGitSystemConfig() in openSystemConfig()
* FS: Add a method to discover the system-wide config file
* FS: Extend readPipe() to optionally take additional environment
* FS: Document readpipe()'s encoding parameter
* Split discoverGitPrefix() code out into discoverGitExe()
* Equalize discoverGitPrefix() implementations between POSIX and Win32
* Move resolveGrandparentFile() to the base class for wider use

* Replace deprecated release() methods by close() in Merger

* Add missing @since tag to DiffInterruptedException

* Add tests for checking out tags with CheckoutCommand

* Revert "Add a method to DfsOutputStream to read as an InputStream"
* Add a Merger.merge method that makes flushing optional
* Teach mergers to use ObjectInserter.newReader()
* Add a method to ObjectInserter to read back inserted objects

* Merge branch 'stable-3.3'

* Static import OBJ_* constants into PackWriter

* NameRevCommand: Use ~ notation for first parents of merges

* Add support for rebase interactive 'edit' command