Switch to Play 3 and Pekko, add support for Scala 3

[mkurz]

@fdimuccio All tests pass for me, also when cross testing with Scala 3. I published locally and it works also.

Can you please merge and publish as 0.10.0? Thanks!

[mkurz]

Ready to review and merge :+1:

[mkurz]

@fdimuccio Can you restart the tests? Seems they were hanging? Thanks!

[mkurz]

@fdimuccio Any chance you can look at this today, thanks!

[fdimuccio]

Sorry for the late reply, It looks good, tests too. Thank you again.

[mkurz]

Great, thanks! Looking forward to the 0.10.0 release ;)

[mkurz]

Great! It's here:

• https://repo1.maven.org/maven2/com/github/fdimuccio/play2-sockjs_3/0.10.0/
• https://repo1.maven.org/maven2/com/github/fdimuccio/play2-sockjs_2.13/0.10.0/