ci: pin minreq to 2.13.2, base64ct to 1.6.0 for MSRV#1886

ValuedMammal merged 2 commits intobitcoindevkit:masterbitcoindevkit/bdk:masterfrom

luisschwab:ci/msrv-base64ctluisschwab/bdk:ci/msrv-base64ctCopy head branch name to clipboard