chore: release 2.0.0-rc.20

Merge pull request bootstrap-vue#3096 from bootstrap-vue/dev

chore: release 2.0.0-rc.19

Merge pull request bootstrap-vue#3049 from bootstrap-vue/dev

chore: release v2.0.0-rc.18

Merge pull request bootstrap-vue#2978 from bootstrap-vue/dev

chore: release 2.0.0-rc.17

Merge pull request bootstrap-vue#2876 from bootstrap-vue/dev

chore: release v2.0.0-rc.16

chore(release): BootstrapVue v2.0.0-rc.15

chore: release v2.0.0-rc.14

chore: release v2.0.0-rc.13

chore: Release Bootstrap-Vue v2.0.0.rc12

chore: Release Bootstrap-Vue v2.0.0.rc12

chore(release): 2.0.0-rc.11