tchrpc: change FundChannel endpoint to POST

[GeorgeTsagk]

Closes #1219

[coveralls]

Pull Request Test Coverage Report for Build 12049818174

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 9 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.02%) to 40.864%

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Files with Coverage Reduction	New Missed Lines	%
asset/asset.go	2	81.13%
tapchannel/aux_leaf_signer.go	3	36.31%
tapgarden/caretaker.go	4	68.5%

Totals
Change from base Build 12038519798:	0.02%
Covered Lines:	25724
Relevant Lines:	62950

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💛 - Coveralls

[GeorgeTsagk]

Hey @V0nMis3s, thanks for taking a look at the PR

Instead of directly modifying the .pb.gw.go file, the appropriate place to make these changes is in the .proto file (taprpc/tapchannelrpc/tapchannel.proto). Specifically:

This was actually automated and was generated by running make rpc (check the Makefile section). The only change that had to be made was in the tapchannel.yaml file, which we use to map the rpc methods to rest endpoints

[V0nMis3s]

Hey @GeorgeTsagk, thank you for the explanation! I assumed the mapping was automatically handled by the default rules of grpc-gateway, and I didn’t realize the tapchannel.yaml file was being used to map the RPC methods to REST endpoints. Thanks for pointing that out!

[gijswijs]

LGTM 🎉