Add munit-cats-effect 2.0 working example

[valencik]

I've published typelevel/munit-cats-effect#223 locally and tested that filtering suite level resource fixtures works as expected.

Running test in sbt yields the expected:

test                                                                              [40/129]
[info] compiling 1 Scala source to /Users/valencik/projects/munit-fixture-suite-filtering/target/scala-2.13/test-classe
s ...                                                      
### beforeAll is running ###                               
### myFixture apply() ###
### myFixture apply() ###
### afterAll is running ###                                                                                            
example.MySuite:
  + test1 0.016s
  + test2 0.001s
### resource fixture acquired ###
### resource fixture released ###
example.MyCatsEffectSuite:
  + test1 0.005s                                           
  + test2 0.004s
[info] Passed: Total 4, Failed 0, Errors 0, Passed 4  

And running testOnly -- --exclude-categories=example.Slow correctly excludes all tests and does not run their fixtures!

example.MySuite:                                           
example.MyCatsEffectSuite:                                                                                             
[info] Passed: Total 0, Failed 0, Errors 0, Passed 0                                                                   
[success] Total time: 0 s, completed Jun. 25, 2022, 10:20:16 a.m.