GHA migration part 2: Remove drone spec, drop Drone CI (#26)

* chore: remove drone spec

* drop some leftover drone refs

Author: andreas-kupries

.drone.yml

@@ -9,7 +9,7 @@ RUN if [[ "${ARCH}" == "amd64" ]]; then \
     curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s v1.54.2; \
     fi
 
-ENV DAPPER_ENV REPO TAG DRONE_TAG
+ENV DAPPER_ENV REPO TAG
 ENV DAPPER_SOURCE /go/src/github.com/rancher/kube-api-auth
 ENV DAPPER_OUTPUT ./bin ./dist
 ENV DAPPER_DOCKER_SOCKET true

Dockerfile.dapper

@@ -4,8 +4,8 @@ if [ -n "$(git status --porcelain --untracked-files=no)" ]; then
     DIRTY="-dirty"
 fi
 
-COMMIT=$(git rev-parse --short HEAD)
-GIT_TAG=${DRONE_TAG:-$(git tag -l --contains HEAD | head -n 1)}
+COMMIT="$(git rev-parse --short HEAD)"
+GIT_TAG="$(git tag -l --contains HEAD | head -n 1)"
 
 if [[ -z "$DIRTY" && -n "$GIT_TAG" ]]; then
     VERSION=$GIT_TAG