build(ci): improve caching efficiency in ci

src/main/Dockerfile

@@ -2,19 +2,17 @@
 FROM maven:3.9.6-eclipse-temurin-21 AS builder
 WORKDIR /app
 COPY pom.xml .
+RUN --mount=type=cache,target=/root/.m2 mvn dependency:go-offline -B
 COPY src ./src
-RUN mvn clean package -DskipTests
-
+RUN --mount=type=cache,target=/root/.m2 mvn clean package -DskipTests -B
 
 # Run stage
-FROM eclipse-temurin:21-jdk
-
+FROM eclipse-temurin:21-jre
 # dependencies
 RUN apt-get update && \
-    apt-get install -y ffmpeg && \
+    apt-get install -y --no-install-recommends ffmpeg && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
-
 WORKDIR /app
 COPY --from=builder /app/target/*.jar app.jar
 EXPOSE 8080