Activate dual funding by default

[t-bast]

And update the release notes.

[remyers]

Looks good; just a few nits/typos in the release notes.

I couldn't find the explanation of the switch in MinimalNodeFixture from DummyOnChainWallet to SingleKeyOnChainWallet.

I can see that tests fail without that change, but some more information about the switch would make that change easier to review.

[t-bast]

I couldn't find the explanation of the switch in MinimalNodeFixture from DummyOnChainWallet to SingleKeyOnChainWallet.

Right, that's because the DummyOnChainWallet is overriding the makeFundingTx function which is used for single-funded channels, but its override of the fundTransaction function that is used for dual-funding is basically a no-op that returns the transaction as-is. This breaks dual funding entirely because it doesn't really return a funded transaction.

The SingleKeyOnChainWallet is a better mock for an on-chain wallet that supports funding transactions, which makes it work for dual funding tests.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.93%. Comparing base (fd0cdf6) to head (e551ecf).

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2825      +/-   ##
==========================================
- Coverage   85.99%   85.93%   -0.06%     
==========================================
  Files         219      219              
  Lines       18453    18453              
  Branches      766      766              
==========================================
- Hits        15869    15858      -11     
- Misses       2584     2595      +11     

see 8 files with indirect coverage changes

[remyers]

Looks ready to go.