CompatHelper: bump compat for CommonMark to 0.9, (keep existing compat) (#900)

Co-authored-by: CompatHelper Julia <compathelper_noreply@julialang.org>

Author: github-actions[bot]

Project.toml

@@ -11,7 +11,7 @@ PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
 TOML = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
 
 [compat]
-CommonMark = "0.5, 0.6, 0.7, 0.8"
+CommonMark = "0.5, 0.6, 0.7, 0.8, 0.9"
 Glob = "1.3"
 JuliaSyntax = "^0.4.10"
 PrecompileTools = "1"