CHASE 0.4.2

Changed:

• is_implementation(m, c) and is_environment(e, c) are the new names of
  implements(m, c) and accepts(c, e), after the terms of the theory
  (M is an implementation of C, E is an environment of C); the environment
  now comes first, as the implementation. The old names still work, with a
  DeprecationWarning. Command line: --implementation MODEL C (was
  --implements, still read) and the new --environment MODEL C. MCP
  server: the tools are named is_implementation and is_environment.

New:

• conjoin(..., discharge=True): the result keeps the terms and is the
  same contract as the conjunction. Each guarantee is guaranteed under the
  assumptions of its contract that the other's do not imply; when the
  assumptions of one contract imply those of the other, the assumption is
  theirs and has no disjunction (with the same assumptions, (A, G1 & G2)).
• Docker image published on ghcr.io/chase-cps/chase at each release
  (docker pull ghcr.io/chase-cps/chase), without nuXmv, whose license does
  not allow redistribution: the checks use NuSMV, built from its sources
  without zChaff (LGPL), and chase-cps install nuxmv --accept-license adds
  nuXmv in a container. The image also has Yosys (yowasp-yosys) and the
  chase-cps command; the demo suite runs Charger, LMFSM, and AHB with
  NuSMV, and BufferSwap.
• chase-cps install nusmv says that the build of FBK is linked with
  zChaff, for non-commercial use only.
• CONTRIBUTING.md: reporting bugs, building and testing, and proposing
  changes.