Quantum-TII/qibo: Qibo 0.1.3

What's Changed Fix issue with tf slicing (#345) @stavros11 Hamiltonian expectation for density matrices (#344) @stavros11 Measurement fixes (#325) @stavros11 Fix controlled by Y gates for custom backend (#343) @stavros11 Metropolis algorithm for sampling shots (#332) @stavros11 Speeding up Metropolis for frequency (#338) @scarrazza Move state reshape in gates (#340) @stavros11 Add nshot switcher (#341) @scarrazza PartialTrace gate for density matrices (#335) @stavros11 Fixing circuit.draw misalignment (#334) @scarrazza Fix gap callback for degenerate Hamiltonians (#329) @stavros11 Fix einsum in density matrix traceout (#328) @stavros11 Make DistributedState custom operator free (#323) @stavros11 adding Windows support (#316) @scarrazza Fix old tests for Windows (#319) @stavros11 Detach custom operators (#317) @scarrazza Fix custom operator imports in tests (#318) @stavros11 upgrading to tf 2.4.1 (#315) @scarrazza State abstraction (#314) @stavros11 MaxCut Hamiltonian (#311) @scarrazza Symbolic Hamiltonian fixes (#312) @scarrazza Tests that run without Tensorflow (#310) @stavros11 Circuit viewer (#308) @scarrazza small fixes (#307) @scarrazza Backend abstraction (#303) @stavros11 Parallel circuit evaluation (#304) @scarrazza custom initial_state (#305) @scarrazza custom initial_state GPU (#306) @scarrazza Documenting custom VQC optimizations (#298) @scarrazza Updating wheels with cuda 11 (#301) @scarrazza Upgrading tf to 2.4.0 (#280) @scarrazza Create base callbacks (#296) @stavros11 Fix test failure on GPU for parallel lbfgs (#297) @scarrazza Trainable flag for parametrized gates (#294) @stavros1