Update go-perun to v0.6.1

Description

v0.6.1 is not a tagged version, but points to cf9279c99f73 commit on dev branch as it has fix for a bug that was introduced in v0.6.0.
This update is necessary to use changes that will be added to the develop branch.
Update perun-node to include the following breaking changes:
- Call Register before Settle.
- Settle and Settle Secondary methods are merged. Now Settle takes a second argument to differentiate between primary and secondary settle.
- Changes in NewTransactor API.
- Watcher takes a callback that handles Registered & Concluded events.
Add a hard coded blocktime to wait before calling register / settle for the user who did not initate close. This is for a temporary workaround and will be removed once a function to wait for n blocks is added in go-perun.

Three follow up issues are to be created:

[x] Currently only collaborative-close is tested in Test_Integ_Role. Add a new test case for non-collaborative-close as well.
[x] Add a functionality in go-perun to wait for n blocks and use it in instead of hard coded waits in session/channel.go.
[x] Check why settle does not wait even when secondary option is set to true (in go-perun).

Relevant issue

Closes #151

Testing

All existing tests should pass. Updated some of the tests for the changes introduced in go-perun.

Steps to run the tests

In one terminal:

ganache-cli -b 1 --account="0x1fedd636dbc7e8d41a0622a2040b86fea8842cef9d4aa4c582aad00465b7acff,100000000000000000000" --account="0xb0309c60b4622d3071fad3e16c2ce4d0b1e7758316c187754f4dd0cfb44ceb33,100000000000000000000"

In another terminal:

go test -cover -p 1 -count=1 -tags=integration ./...

Checklist

[x] Name is added to the NOTICE file, if it is not present already.
[x] Changes are rebased onto the target branch.

hyperledger-labs / perun-node

Update go-perun to v0.6.1 #161

Description

Category

Relevant issue

Testing

Steps to run the tests

Checklist