0.9.0

new

• implemented file/directory locking in the CLI to prevent multiple CLI processes from interfering with one another

changes

• exercise download errors contain information about downloaded/failed exercises
• updated output format to contain variant tags, see tmc-client/api for example files and tmc-client/src/output.rs for the actual output struct
• downloads exercises in parallel
• removed core checkstyle and core run-tests as redundant
• when parsing a tmc-server error response as JSON fails, return a generic HTTP error instead of a deserialization error
• do not crash on parsing non-UTF-8 files

etc

• refactored and added tests to CLI