Issue description:

I'm trying to build TinkersConstruct for 1.16.1 but I have this error

If crashed, link to crash report (use a site such as pastebin):

Task :reobfJar FAILED
Exception in thread "main" java.lang.IllegalArgumentException: Unsupported class file major version 55
at org.objectweb.asm.ClassReader.(ClassReader.java:166)
at org.objectweb.asm.ClassReader.(ClassReader.java:148)
at org.objectweb.asm.ClassReader.(ClassReader.java:136)
at org.objectweb.asm.ClassReader.(ClassReader.java:237)
at net.md_5.specialsource.JarRemapper.remapClassFile(JarRemapper.java:221)
at net.md_5.specialsource.JarRemapper.remapJar(JarRemapper.java:187)
at net.md_5.specialsource.SpecialSource.main(SpecialSource.java:273)

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':reobfJar'.

Process 'command 'C:\Program Files\Java\jdk-11.0.8\bin\java.exe'' finished with non-zero exit value 1

• Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 6.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/5.6.2/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 15s
8 actionable tasks: 3 executed, 5 up-to-date

Versions:

• Minecraft: 1.16.1
• Forge: 1.16.1
• Mantle:
• Tinkers Construct: 1.16

Can it be reproduced with just Tinkers Construct? If not, list the other mods required to reproduce the issue.