Update library used for toml support

[cebarks]

The currently used toml library (github.com/BurntSushi/toml) has officially been marked as unmaintained by its owner. As such, it might be wise to move to a new library (support for newer versions of the TOML spec as burntsushi/toml only supports v0.4.0, bug/security fixes, etc).

[codecov[bot]]

Codecov Report

Merging #63 (00988e1) into master (ce3ee7f) will decrease coverage by 0.68%. The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master      #63      +/-   ##
==========================================
- Coverage   89.79%   89.11%   -0.69%     
==========================================
  Files           1        1              
  Lines         245      248       +3     
==========================================
+ Hits          220      221       +1     
- Misses         17       18       +1     
- Partials        8        9       +1     

Impacted Files	Coverage Δ
cleanenv.go	89.11% <50.00%> (-0.69%)	:arrow_down:

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[cebarks]

Realized i never mentioned the new library this switches to is: https://github.com/pelletier/go-toml

[ilyakaznacheev]

Closed since we already use the new github.com/BurntSushi/[email protected].

Maybe we will switch to go-toml in the future, but now I see no reason to do so.