Modernizing many things

- use hashicorp/setup-terraform action
- bump terraform requirement to 0.13
- bump digitalocean provider requirement to 1.22
- bump to latest nvm
- remove a bunch of unnecessary quotes

spoke-app-provision

@@ -116,7 +116,7 @@ _run_spoke0() {
 
   if ! command -v nvm; then
     curl -fsSL \
-      https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.2/install.sh | bash
+      https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
     set +o errexit
     set +o xtrace
     # shellcheck source=/dev/null