Fixed version string

Merge branch 'master' into release-candidate

Version to 0.7.3

Merge branch 'master' into release-candidate

Release v0.7.1

* Supporting MS Windows (in addition to Linux & MacOS).
* Support for Isabelle2022.
* New tactic `sp` (strongest postcondition).
* Strongly extended `swap` tactic: Can now swap program fragments with common variables and rewrite fragments during swap.
  Note: invocation syntax has changed.
* New tactic `rewrite`: Substitute lines in program by other denotationally equivalent lines.
* New type of subgoal: denotational equivalence. (Supported by tactics `byqrhl`, `inline`, `rewrite` so far.)
* `proofgeneral.sh` / `proofgeneral.ps1` scripts: Do not ignore `.emacs` file with user configuration
  (add `-q` to ignore it in case of trouble).
* `print goal` command for showing current goal in a way suitable for copy & paste to Isabelle theory.
* Proof goal shows line numbers.
* Isabelle startup script `run-isabelle.sh` renamed to `isabelle.sh` / `isabelle.ps1`.
* Various bugfixes.

Created new release.

Updated version to 0.6

Release version 0.5

Artifact accompanying POPL 2019 paper "Quantum Relational Hoare Logic"

Version corresponding to arXiv v2