Scala 3

[tpolecat]

Scala 3 support. This will be tagged as v0.10.0-M1 when merged (new deprecations will be since="0.10.0").

In retrospect I should have done the switch to MUnit as an orthogonal PR. Sorry about that, I was already part-way in before I realized I would need to do it so I just kept on going.

Notable changes:

• doobie no longer relies on TypeTag, it uses TypeName instead.
• Line number macros have been internalized; there is no longer a dependency on lihaoyi/sourcecode.
• Tests have been migrated from specs2 to MUnit. This is the cause of most of the churn in this PR.
• The enum package has been renamed enumerated. For Scala 2 users an enum object remains behind as a bridge.
• Shapeless is not used in the Scala 3 version. Instances are derived via Tuple and Product rather than HList and Generic.
• Get and Put instances cannot be derived for unary AnyVals in Scala 3. See Support Mirrors for value classes scala/scala3#7023
• Deprecated JDBC and Postgres Driver methods have been removed from the Free APIs.

Progress

• bench
• core (compile)
• core (tests)
• docs ⚠️ Scala 2 only
• example
• free
• h2
• hikari
• postgres-circe ⚠️ Scala 2 Only
• postgres
• quill ⚠️ Scala 2 Only
• refined
• scalatest ⚠️ Scala 2 Only
• specs2 ⚠️ Scala 2 Only