hax actions

This repository provides GitHub actions for installing and configuring the hax toolchain and its dependencies.

This GitHub action:

• Installs the hax toolchain (plus cargo and rustc);
• Installs F* (the version of F* is frozen and pinned in hax);
• Provides the environment variable HAX_PROOF_LIBS, HAX_LIB and HACL_HOME, which are commonly expected by our makefiles that verify hax-extracted code with F*.

By default, the action uses the latest hax on main on the repository github:hacspec/hax. The inputs hax_repository and hax_reference can be set to change this behavior.

Running this action is fast: it takes about a minute and a half (we use cachix: so commits on the main branch of hax are pre-built).