Update version and CHANGELOG.md

Fix chained session deadlock

The chained session tests now makes one of the next session URLs artifically slow, and simulates polling using the waitSessionFinished() helper function, which tries to lock the session like the /status endpoints do.

If the next session URL responds so slowly that a polling lands in the middle, then:
1) the poll HTTP handler locks the session store, and first tries to lock the session before unlocking the session store;
2) the /proofs HTTP handler has the session locked, and tries locking the session store when the next session URL finally responds.

But 1) still has the sessionstore lock, so 2) cannot complete and unlock the session lock, so 1) cannot complete and release the session store lock. Deadlock.

The fix is to make the unlocking of the memory session store in 1) immediate and not conditional on locking the session.

Improve scheme language validation

Fix: go-sse cannot be used in combination with go-chi middleware

Chore: make it possible to trigger weekly checks manually

Fix: TestRevocationAll/Cache test should take into account network delay

Feat: added option for static sessions and session packages to irma session command

Refactor session tests