Pyvmlib

Dropped Python <=3.3 support other than 2.7. Added newer Python build targets 3.7, 3.8, 3.9, 3.10.

Moved from Travis CI to GitHub actions and gated deployment on passing of builds on all supported Python versions.

Multiple minor changes to setup.py/README

Update TLS protocol version from v1 to the highest negotiated version
Add 3.6 to the supported Python versions

This version adds a `folder` argument to `get_vm`. Searching within a specific folder for a VM is near instant, while the old/default behaviour of searching the whole VM list is an `O(N)` operation.

There's also a new function for finding VMs by their Instance UUID (`get_vm_by_instance_uuid`), which is fast, even if you don't know what folder the VM is in.

This is required to get information about expired processes that were started with the `interactive` flag.

We noted that if a file upload failed (perhaps if an intermediate HTTP proxy rejected the size of the upload file), there was no error raise.

We now check that the HTTP server gives a success result code and raise an Exception if it doesn't.

This release improves the Exceptions generated by the `connect()` method. If you were handling the underlying pyvmomi Exceptions before, you'll need to switch to handling `VmNotFoundException`, `InvalidCredentialsException`, and `HostConnectException`.