Remove GitHub actions as they do not work with public repos yet

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

.github/dependabot-approve.workflow

-workflow "Auto-approve Dependabot PRs" {
-  resolves = ["Auto Approve"]
-  on = "push"
-}
-
-action "Auto Approve" {
-  uses = "hmarr/auto-approve-action@v1.0.0"
-  secrets = ["GITHUB_TOKEN"]
-}

.github/main.workflow

-workflow "Approve Dependabot PRs" {
-  resolves = ["hmarr/auto-approve-action@v1.0.0"]
-  on = "push"
-}
-
-action "Filters for GitHub Actions" {
-  uses = "actions/bin/filter@3c0b4f0e63ea54ea5df2914b4fabf383368cd0da"
-  args = "actor dependabot-preview"
-}
-
-action "hmarr/auto-approve-action@v1.0.0" {
-  uses = "hmarr/auto-approve-action@v1.0.0"
-  needs = ["Filters for GitHub Actions"]
-  secrets = ["GITHUB_TOKEN"]
-}