fix: hadolint DL3018, remove quoted strings

Dockerfile

@@ -1,16 +1,11 @@
-FROM "alpine:3.23"
+FROM alpine:3.23
 LABEL maintainer="Cabillot Julien <dockerimages@cabillot.eu>"
 
+# hadolint ignore=DL3018
 RUN apk add --no-cache mysql-client && \
-    rm -rf "/usr/share/apk/keys" && \
+    rm -rf /usr/share/apk/keys && \
     adduser -D muser
 
-# Add Tini
+USER muser
-#ENV "TINI_VERSION" "v0.16.1"
-#ADD "https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini" "/tini"
-#RUN chmod +x "/tini"
-#ENTRYPOINT ["/tini", "--"]
-
-USER "muser"
 
 ENTRYPOINT [ "/usr/bin/mysql" ]