Hotfix a1.2.1

Changes

• Fixed script building not working #22
• Added MC Sync for 1.21.120 #20
• Added error checking for MC Sync

What's Changed (Dependabot)

• Bump com.formdev:flatlaf from 3.6.1 to 3.6.2 by @dependabot[bot] in #18
• Bump com.google.guava:guava from 33.0.0-jre to 33.5.0-jre by @dependabot[bot] in #12
• Bump org.junit.jupiter:junit-jupiter from 5.13.4 to 6.0.0 by @dependabot[bot] in #17

Full Changelog: a1.2...a1.2.1