Start moving from gogo protobuf

[gammazero]

Gogo protobuf is deprecated. Move ipld/unixfs away from it.

Separate PRs for:

• ipld/unixfs: move ipld/unixfs from gogo protobuf #840
• ipld/merkledag: move ipld/merkledag from gogo protobuf #841

[codecov]

Codecov Report

Attention: Patch coverage is 47.51553% with 169 lines in your changes missing coverage. Please review.

Project coverage is 61.77%. Comparing base (24b6bc3) to head (e386e42).

Files with missing lines	Patch %	Lines
bitswap/message/pb/message.pb.go	36.45%	126 Missing and 3 partials ⚠️
bitswap/message/message.go	67.39%	13 Missing and 2 partials ⚠️
filestore/pb/dataobj.pb.go	76.36%	12 Missing and 1 partial ⚠️
filestore/util.go	0.00%	7 Missing ⚠️
filestore/fsrefstore.go	60.00%	4 Missing ⚠️
bitswap/testnet/virtual.go	0.00%	1 Missing ⚠️

@@            Coverage Diff             @@
##             main     #839      +/-   ##
==========================================
+ Coverage   60.37%   61.77%   +1.40%     
==========================================
  Files         243      243              
  Lines       31119    29952    -1167     
==========================================
- Hits        18787    18502     -285     
+ Misses      10648     9881     -767     
+ Partials     1684     1569     -115     

Files with missing lines	Coverage Δ
routing/offline/offline.go	72.72% <ø> (ø)
bitswap/testnet/virtual.go	68.42% <0.00%> (ø)
filestore/fsrefstore.go	42.45% <60.00%> (+0.54%)	⬆️
filestore/util.go	0.00% <0.00%> (ø)
filestore/pb/dataobj.pb.go	73.01% <76.36%> (+34.69%)	⬆️
bitswap/message/message.go	82.02% <67.39%> (-2.41%)	⬇️
bitswap/message/pb/message.pb.go	35.34% <36.45%> (+5.60%)	⬆️

... and 10 files with indirect coverage changes

[lidel]

Triage note:

• needs async review but we want to go ahead and see if anyone reports issues during Kubo 0.34.0-rc1
• just make it prominent in changelog to urge people who depend ond eterministic CIDs to double-check before upgrading

[gammazero]

@lidel bump