Fs.smbfs

Fixed
- SMB share names are now matched case-insensitively ([28](https://github.com/althonos/fs.smbfs/pull/28)).
- When created with `direct_tcp=True`, `SMBFS` will not attempt to use NetBIOS anymore to find a missing IP/hostname ([25](https://github.com/althonos/fs.smbfs/pull/25)). Closes [#24](https://github.com/althonos/fs.smbfs/issues/24).

Added
- Explicit support for Python 3.9.
- This changelog file.
- `SMBFS.upload` (resp. `download`) implementation using the `SMBConnection.storeFile` (resp. `retrieveFile`) method.
- `SMBFS.geturl` implementation for the `download` purpose.
- `SMBFile.mode` property to expose the mode the file was created with.
- `SMBFile.readinto` method using a zero-copy implementation.

Changed
- `SMBFS.openbin` will open a new connection for every new file.
- `SMBFS.readbytes` (resp. `writebytes`) now uses `SMBFS.download` (resp. `upload`).
- Mark the project as *Stable* in `setup.cfg` classifiers.
- Switched from Travis-CI and AppVeyor to GitHub Actions for continuous integration.
- Rewrote `README.rst` in Markdown format.

Added
- Explicit support for `v1.2.6` of PySMB.

Added
- Explicit support for `v1.2.5` of PySMB.

Added
- Explicit support for `v1.2.4` of PySMB.

Added
- Explicit support for `v1.2.3` of PySMB.