Swap to using open_text from importlib_resources

[talister]

Change Description

read_text() from importlib_resources is now deprecated and the github actions is complaining

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Solution Description

Swapped from doing a toml.loads of the string returned by pkg_resources.read_text() to a toml.load on the file pointer returned by pkg_resources.open_text() from the newer files() interface

Code Quality

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