rp-adapter: update hydra

[llorllale]

We are using a really old version of Hydra (1.3.2) and the latest was just released today (1.8.5).

Several security vulnerabilities have been addressed since 1.3.2:

• 1.4.0: potential replay of private_key_jwt JWTs when performing client authorization (BREAKING CHANGE: This patch requires a new SQL Table which needs to be created using hydra migrate sql. No other breaking changes have been introduced by this patch.)
• 1.8.5: CVE-2020-15234, CVE-2020-15223, CVE-2020-15233

Other changes of note:

• 1.5.0-beta1: introduces a breaking change that requires running hydra migrate sql before applying this release.
• 1.5.1: does not contain breaking changes but please run hydra migrate sql once you have backed up the database
• 1.7.0: not relevant for us: breaking change affecting user consent revocation flow
• 1.7.4: requires SQL migrations