Changes of version 9.0.0

• [Breaking]: Add support for expression-style metric override. The old [metric-override.multiplies] and [metric-override.adds] are no longer supported (#1181).
• Fix motion-serifed N's broken shape (#1170).
• Fix bar-serif overlapping in Latin Small H-bar (U+0127) and Cyrillic Small Dje (U+0452) in Sans subfamily's with-serif variants (#1171).
• Add flat-boundary brace shape (#1172).
• Apply variants of I/i and J/j to Dutch letters U+0132 and U+0133 (#1174).
• Make dot size, period size and accent size / placement configurable (#1169, #1176).
• Make variants of 0 apply to APL Functional Symbol Zilde (U+236C) and Circled Zero with Slash (U+1F10D) (#1178).
• Add enclosed sans-serif digits.
• Fix italic derived letters regression in 8.0.