refactor(ko): switch to buster base image

ko/Dockerfile

@@ -1,4 +1,12 @@
-FROM docker.io/golang:1.19-alpine
+FROM docker.io/golang:1.19-bullseye as downloader
 
-RUN echo https://dl-cdn.alpinelinux.org/alpine/edge/testing/ >> /etc/apk/repositories && \
+RUN apt-get update && \
-	apk add -U --no-cache ko
+	apt-get install -y \
+		curl \
+		jq && \
+	export KO_VERSION=$(curl https://api.github.com/repos/ko-build/ko/releases | jq -r '. | first |.tag_name | capture("(?<version>[[:digit:]]+\\.[[:digit:]]+\\.[[:digit:]]+)") | .version') && \
+	curl -L "https://github.com/ko-build/ko/releases/download/v${KO_VERSION}/ko_${KO_VERSION}_Linux_x86_64.tar.gz" | tar xvz -C /tmp
+
+FROM docker.io/golang:1.19-bullseye as final
+
+COPY --from=downloader /tmp/ko /usr/local/bin/ko