Docker build failure

$ docker build -t pw-docker-bug -f Dockerfile .
Sending build context to Docker daemon     64kB
[WARNING]: Empty continuation line found in:
    RUN         sed -i "external url"        apk upgrade --no-cache &&  RUN mkdir /opt/app-root     && chown node : node /opt/app-root
[WARNING]: Empty continuation lines will become errors in a future release.
Step 1/21 : ARG nodeBase=node14-base
Step 2/21 : FROM node:14.17.6-alpine3.13 as node14-base
14.17.6-alpine3.13: Pulling from library/node
4e9f2cdf4387: Pull complete 
6767681722af: Pull complete 
e5e37393f133: Pull complete 
7a72b80664d6: Pull complete 
Digest: sha256:bd7f3879132b126e5f6770e7e50e223c2e74c1f223d27bfd06dd71a17ebb8fc3
Status: Downloaded newer image for node:14.17.6-alpine3.13
 ---> f05f6c17701e
Step 3/21 : FROM ${nodeBase} as pro-node-base
 ---> f05f6c17701e
Step 4/21 : RUN         sed -i "external url"        apk upgrade --no-cache &&  RUN mkdir /opt/app-root     && chown node : node /opt/app-root
 ---> Running in 2d97b0b122d2
sed: unrecognized option: no-cache
BusyBox v1.32.1 () multi-call binary.

Usage: sed [-i[SFX]] [-nrE] [-f FILE]... [-e CMD]... [FILE]...
or: sed [-i[SFX]] [-nrE] CMD [FILE]...

        -e CMD  Add CMD to sed commands to be executed
        -f FILE Add FILE contents to sed commands to be executed
        -i[SFX] Edit files in-place (otherwise sends to stdout)
                Optionally back files up, appending SFX
        -n      Suppress automatic printing of pattern space
        -r,-E   Use extended regex syntax

If no -e or -f, the first non-option argument is the sed command string.
Remaining arguments are input files (stdin if none).
The command '/bin/sh -c sed -i "external url"        apk upgrade --no-cache &&  RUN mkdir /opt/app-root     && chown node : node /opt/app-root' returned a non-zero code: 1

@yury-s pls update line # 18 with docker url. [Step 4/21 : RUN sed -i "external url" ]