fix: invalid chars in image name

Dockerfile

@@ -1,3 +1,3 @@
 FROM gcr.io/kaniko-project/executor:v1.23.2-debug
-COPY build.sh /usr/local/bin/
-ENTRYPOINT ["build.sh"]
+COPY entrypoint.sh /usr/local/bin/
+ENTRYPOINT ["entrypoint.sh"]

entrypoint.sh

@@ -15,7 +15,7 @@ EOF
 
 if [ -z "$IMAGEAPP" ]; then
     REGISTRY="$(echo "$GITHUB_SERVER_URL" | sed 's .*://  ')"
-    IMAGEAPP="$REGISTRY/$INPUT_IMAGE"
+    IMAGEAPP="$REGISTRY/$(printf '%s' "$INPUT_IMAGE" | tr '[:upper:]' '[:lower:]' | tr -c '[:lower:][:digit:]-:_' _)"
 fi
 
 /kaniko/executor \