v1.0.10

1. Update showdowns deps to version 0.6.7.

v1.0.8

1. Update showdowns deps to version 0.6.4.
2. Support echarts and abcjs plugin.

v1.0.5

1. Update showdowns deps to version 0.5.7.

v1.0.4

1. Update @jhuix/showdowns is v0.5.5 and vue is v2.6.10, etc.
2. Add default dummy text is english when set the locals to except for zh-cn and zh-cht.