Bump com.vladsch.flexmark:flexmark from 0.62.2 to 0.64.8

Bumps [com.vladsch.flexmark:flexmark](https://github.com/vsch/flexmark-java) from 0.62.2 to 0.64.8.
- [Commits](https://github.com/vsch/flexmark-java/commits)

---
updated-dependencies:
- dependency-name: com.vladsch.flexmark:flexmark
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

build.gradle

@@ -78,10 +78,10 @@ dependencies {
     implementation group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.15.2'
 
     //FlexMark
-    implementation group: 'com.vladsch.flexmark', name: 'flexmark', version: '0.62.2'
-    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-gfm-strikethrough', version: '0.62.2'
-    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-tables', version: '0.62.2'
-    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-gfm-tasklist', version: '0.62.2'
+    implementation group: 'com.vladsch.flexmark', name: 'flexmark', version: '0.64.8'
+    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-gfm-strikethrough', version: '0.64.8'
+    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-tables', version: '0.64.8'
+    implementation group: 'com.vladsch.flexmark', name: 'flexmark-ext-gfm-tasklist', version: '0.64.8'
 
     // Protobuf
     implementation group: 'com.google.protobuf', name: 'protobuf-kotlin-lite', version: '3.23.3'