Fix CRLF line endings on entrypoint script causing sh\r runtime crash on Alpine

Dockerfile

@@ -25,6 +25,9 @@ RUN npm install --omit=dev
 COPY backend ./backend
 COPY --from=builder /site/_site ./public
 COPY entrypoint.sh /entrypoint.sh
+
+# Behebt Windows CRLF Zeilenumbrueche, ansonsten stuerzt Alpine mit "sh\r: not found" ab!
+RUN sed -i 's/\r$//' /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
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