Cherry pick 6ee9bc03 - Add a note on rust compiler testing and compatibility #726

[alamb]

Manual cherry-pick of 6ee9bc0 originally appearing in #726

Note it also contains some content from master about versioning which I think is ok.

[codecov-commenter]

Codecov Report

Merging #754 (9f07029) into active_release (9f7707c) will increase coverage by 0.00%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           active_release     #754   +/-   ##
===============================================
  Coverage           82.45%   82.45%           
===============================================
  Files                 167      167           
  Lines               46810    46810           
===============================================
+ Hits                38598    38599    +1     
+ Misses               8212     8211    -1     

Impacted Files	Coverage Δ
parquet/src/encodings/encoding.rs	94.67% <0.00%> (+0.19%)	⬆️

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