gs1.1: feat: add invalid message spam protection

[wemeetagain]

Implements https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.1.md#spam-protection-measures final bullet point

Following the resolution to #105 , we now have a "reason" to reject messages.
This is a slight refactor of PeerScore#rejectMessage and IWantTracer#rejectMessage to align with go-libp2p-pubsub behavior.

• rejectMessage now accepts reason parameter
• PeerScore#ignoreMessage removed in favor of reusing rejectMessage

[codecov-commenter]

Codecov Report

Merging #113 into gsv1.1 will increase coverage by 0.44%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           gsv1.1     #113      +/-   ##
==========================================
+ Coverage   75.93%   76.37%   +0.44%     
==========================================
  Files          22       22              
  Lines        1342     1346       +4     
==========================================
+ Hits         1019     1028       +9     
+ Misses        323      318       -5     

Impacted Files	Coverage Δ
src/tracer.js	100.00% <0.00%> (ø)
src/constants.js	100.00% <0.00%> (ø)
src/index.js	68.57% <0.00%> (+0.31%)	⬆️
src/score/peerScore.js	81.89% <0.00%> (+1.11%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 89bf606...27fe567. Read the comment docs.