docker: Update to PHP 8.3

Updates the base PHP image the panel is built on to PHP 8.3

Dockerfile

@@ -10,7 +10,7 @@ RUN yarn install --frozen-lockfile \
 
 # Stage 1:
 # Build the actual container with all of the needed PHP dependencies that will run the application.
-FROM --platform=$TARGETOS/$TARGETARCH php:8.1-fpm-alpine
+FROM --platform=$TARGETOS/$TARGETARCH php:8.3-fpm-alpine
 WORKDIR /app
 COPY . ./
 COPY --from=0 /app/public/assets ./public/assets