* Add validation to hex decoder

* Update Orbit to I20200115225246 and update dependencies
* Update bazlets and bazel version

* Merge branch 'stable-5.5' into stable-5.6

* UploadPackServlet: Use uploadWithExceptionPropagation
* GitSmartHttpTools: Do not use sideband when sending an error

* dfs: rename ReftableStack to DfsReftableStack
* reftable: add maxUpdateIndex to Reftable

* reftable: increment pointer *after* reading uint16
* reftable: test absense of prefix matching in Reflog
* reftable: enforce ordering for ref and log writes
* reftable: add some more comments

* Determine hard-linking and nlink support per FileStore
* Support reading and writing cookies.

* PushConnectionTest: Open TestRepository in try-with-resource
* MergerTest: Open TestRepository in try-with-resource
* MergeCommandTest: Open TestRepository in try-with-resource
* PackWriterTest: Open TestRepository in try-with-resource

* pgm: Fix missing braces in Describe.run()
* pgm: Handle exceptions in Describe command
* pgm: Handle exceptions in Config command
* pgm: Fix too wide lines in Commit.run()
* pgm: Fix missing braces in Commit.run()
* pgm: Handle exceptions in Commit command
* pgm: Handle exceptions in Clean command
* pgm: Handle GitAPIException in Fetch command

* Skip ignored directories in FileTreeIterator

* Enhance test coverage when core.filemode is false

* PushCertificate: Add toTextWithSignature() method
* PushCertificateParser: Add fromString method
* BaseReceivePack: Add method to override the push cert
* BaseReceivePack: Don't throw from getPushCertificate()
* PushCertificateStore: Return boolean from batch save methods
* Allow saving push certs on a subset of refs

* 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

* Use try-with-resource to close resources in CommitCommand

* TestRepository: Allow setting explicit Change-Id
* TestRepository: Ignore existing Change-Id in message
* TestRepository: Support committing to unborn symref
* TestRepository: Expose some getters for CommitBuilder
* TestRepository: Add methods to amend commits or refs
* TestRepository: Add a reset method to move HEAD around
* TestRepository: Optionally insert Change-Id in commit message

* 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

* Add missing @since tags
* Move org.eclipse.jgit.pgm's resource bundle to internal package

* Don't delta compress garbage objects
* Delete broken DFS read-ahead support
* Optimize DFS object reuse selection code

* Remove throws IOException declaration on filterClean
* Add Object type to Comparable implements declaration
* Remove 4 unboxed warnings

* Allow RepositoryResolver to throw ServiceMayNotContinueException
* Clarify documentation of exceptions in RepositoryResolver