pytket v1.20.0 release

What's Changed

• Add apply_clifford_basis_change_tensor by @sjdilkes in #1005
• BarrierOp and Circuit._add_conditional_barrier by @sjdilkes in #988
• Main by @cqc-alec in #1009
• Tell mypy to warn about unused ignores; remove them. by @cqc-alec in #1010
• update changelog by @cqc-melf in #1017
• Remove unneeded conan install commands. by @cqc-alec in #1016
• fix wasm, update changelog by @cqc-melf in #1021
• Fix handling of range predicates and scratch bits in QASM conversion by @cqc-alec in #1022
• Release/1.20.0 by @cqc-alec in #1024

Full Changelog: v1.19.1...v1.20.0