File.read over File.open for SSLContext

[alieander]

All of these Context certs expect a string. File.open responds to .to_s so this has worked fine until now... However it was then never cleaning up the open File until garbage collection. This change will read the file right into a string and close the file straight away being a bit more resource friendly over time.

[ghost]

@alieander, thanks for your PR! By analyzing the annotation information on this pull request, we identified @freerobby, @bschwartz and @Soulou to be potential reviewers

[bschwartz]

Good 👁 @alieander! Going to bump patch versions and push this up.

[alieander]

: smiles: