Stash 2.1.2 failing with MySQL 5.6 due to "specified key was too long" error

The schema could not be created.
com.atlassian.stash.internal.migration.DefaultMigrationHelper.createSchema(DefaultMigrationHelper.java:117)
com.atlassian.stash.internal.migration.AbstractMigrationMaintenanceTask.setup(AbstractMigrationMaintenanceTask.java:195)
com.atlassian.stash.internal.maintenance.ActiveMaintenanceTaskContext.setup(ActiveMaintenanceTaskContext.java:166)
...
Migration failed for change set liquibase/r1_3/m01.xml::STASHDEV-1023-10::bturner:
Reason: liquibase.exception.DatabaseException: Error executing SQL CREATE INDEX `idx_sta_diff_comment_anchors` ON `stash`.`sta_diff_comment_anchor`(`to_hash`, `file_path`, `from_hash`): Specified key was too long; max key length is 767 bytes:
Caused By: Error executing SQL CREATE INDEX `idx_sta_diff_comment_anchors` ON `stash`.`sta_diff_comment_anchor`(`to_hash`, `file_path`, `from_hash`): Specified key was too long; max key length is 767 bytes:
Caused By: Specified key was too long; max key length is 767 bytes
liquibase.changelog.ChangeSet.execute(ChangeSet.java:347)
liquibase.changelog.visitor.UpdateVisitor.visit(UpdateVisitor.java:27)
liquibase.changelog.ChangeLogIterator.run(ChangeLogIterator.java:58)
...
Error executing SQL CREATE INDEX `idx_sta_diff_comment_anchors` ON `stash`.`sta_diff_comment_anchor`(`to_hash`, `file_path`, `from_hash`): Specified key was too long; max key length is 767 bytes
liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:62)
liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:104)
liquibase.database.AbstractDatabase.execute(AbstractDatabase.java:1091)
...
Specified key was too long; max key length is 767 bytes
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)