Prepare for release v0.3.0

[ap--]

TODOs

• v0.2.2 breaks SMBFilesystem #217
• implement SMBPath and tests #219
• Static analysis of types broken in >=0.2.0 #210
• Add typesafety checks #212
• upath._flavour_sources: update flavours #224
• S3Path.touch with exist_ok=True on existing file raises an error #216
• Behaviour of joinpath when the second path has protocol #213
• relative_to doesn't work for FilePath #214
• Have relative_to return PosixUPath  #215
• Test against 3.13 #221
• Test regressions with Python 3.13 #245
• Heads up: pathlib._PathBase may be coming soon #114
• Inherit from PathBase instead of Path #193
• Inherit from pathlib_abc.PathBase #270
• update readme
• update ci actions