Feature/made it compatible with older nodejs versions

[lenchv]

No description provided.

[codecov-io]

Codecov Report

Merging #3 into master will increase coverage by 0.56%.
The diff coverage is 91.17%.

@@            Coverage Diff             @@
##           master       #3      +/-   ##
==========================================
+ Coverage   86.43%   86.99%   +0.56%     
==========================================
  Files          15       15              
  Lines         339      346       +7     
==========================================
+ Hits          293      301       +8     
+ Misses         46       45       -1     

Impacted Files	Coverage Δ
lib/stream/DigestInputStream.js	85.71% <ø> (-0.96%)	⬇️
lib/encryption/PKCS8Key.js	83.33% <70.00%> (+5.55%)	⬆️
lib/certs/CertificateRegistry.js	83.33% <100.00%> (ø)
lib/encryption/DerValue.js	64.28% <100.00%> (ø)
lib/encryption/KeyProtector.js	95.65% <100.00%> (ø)
lib/keystore/JavaKeyStoreParser.js	90.47% <100.00%> (ø)
lib/stream/InputStream.js	94.73% <100.00%> (+1.87%)	⬆️

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