Issue with LICENSE during image build using Dockerfile

[nsaustin]

I'm not sure if something is different with this 20.3 release, but see below:

sudo ./build.sh 20.3.0.29587 e7631bc87e99ffe259d04ad60bcc8559aa46fbee808295955886c820821c798d
Sending build context to Docker daemon 24.83MB
Step 1/13 : FROM alpine AS builder
---> a187dde48cd2
Step 2/13 : MAINTAINER support@appdynamics.com
---> Running in 964238a90455
Removing intermediate container 964238a90455
---> 0ac47aa8b770
Step 3/13 : LABEL name="AppDynamics Java Agent" vendor="AppDynamics" version="20.3.0" release="1" url="https://www.appdynamics.com" summary="AppDynamics solution for monitoring Java applications" description="AppDynamics agent for monitoring Java applications"
---> Running in a4ea462bc3e3
Removing intermediate container a4ea462bc3e3
---> 6a2011edd6b8
Step 4/13 : ARG APPD_AGENT_VERSION
---> Running in 3c3fec407b5d
Removing intermediate container 3c3fec407b5d
---> 5bb087c31d8e
Step 5/13 : ARG APPD_AGENT_SHA256
---> Running in cae1289ca18e
Removing intermediate container cae1289ca18e
---> 0e77fd64d88e
Step 6/13 : RUN apk --no-cache add unzip
---> Running in 9e9e46f1773c
fetch http://dl-cdn.alpinelinux.org/alpine/v3.11/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.11/community/x86_64/APKINDEX.tar.gz
(1/1) Installing unzip (6.0-r6)
Executing busybox-1.31.1-r9.trigger
OK: 6 MiB in 15 packages
Removing intermediate container 9e9e46f1773c
---> c2fe697c963c
Step 7/13 : COPY AppServerAgent-${APPD_AGENT_VERSION}.zip /
---> 7c7f34201d12
Step 8/13 : RUN if [ "x${APPD_AGENT_SHA256}" != "x" ]; then echo "${APPD_AGENT_SHA256} *AppServerAgent-${APPD_AGENT_VERSION}.zip" >> appd_checksum && sha256sum -c appd_checksum && rm appd_checksum && unzip -oq AppServerAgent-${APPD_AGENT_VERSION}.zip -d /tmp; else unzip -oq AppServerAgent-${APPD_AGENT_VERSION}.zip -d /tmp; fi
---> Running in f0835316a8ce
AppServerAgent-20.3.0.29587.zip: OK
Removing intermediate container f0835316a8ce
---> 38913216bf09
Step 9/13 : ADD LICENSE /licenses/
ADD failed: stat /var/lib/docker/tmp/docker-builder809200304/LICENSE: no such file or directory