Bump `z3` to version 0.6.0 and `z3-sys` to version `0.6.2`

Bump `z3` to version 0.6.0 and `z3-sys` to version `0.6.2`

Bump z3 to 0.5.1 and z3-sys to 0.6.1

Bump z3 to 0.5.1 and z3-sys to 0.6.1

Bump z3 to 0.5.0 and z3-sys to 0.6.0

Bump z3 to 0.5.0 and z3-sys to 0.6.0

z3: Release 0.4.0.

z3-sys: Release 0.5.0.

z3: Bump version for publish.

Bump z3 version to 0.3 for publish.