cannot run due to bedrock-entry.sh operation not permitted

I am seeing this in the container logs:
```
DEBU[0000] Using /data to match uid and gid
DEBU[0000] Resolved UID=5000 from match path
DEBU[0000] Resolved GID=5000 from match path
FATA[0000] Failed to run sub-command error="fork/exec /opt/bedrock-entry.sh: operation not permitted"
DEBU[0000] Using /data to match uid and gid
DEBU[0000] Resolved UID=5000 from match path
DEBU[0000] Resolved GID=5000 from match path
FATA[0000] Failed to run sub-command error="fork/exec /opt/bedrock-entry.sh: operation not permitted"
```
this is running on an Ubuntu machine in digital ocean with this docker version:
```
root@minecraft-docker-01a:~# docker --version
Docker version 20.10.7, build 20.10.7-0ubuntu5~20.04.2
```
I am using this script to start the container:
```shell
#!/bin/bash

mkdir -p /var/lib/minecraft/data/
chown 5000:5000 /var/lib/minecraft -R

# -dit means detach, interactive, pseudo tty. This allows you to attach and detach from stdin
#
# 3G memory should leave some room within the 4G that the VM has?
#
docker run \
-dit \
--restart="on-failure" \
-v /var/lib/minecraft/data:/data:Z \
-p 19132:19132/udp \
-u 5000:5000 \
-e VERSION=LATEST \
-e SEED="-479112237913370" \
-e OPS="DerElbenkoenig" \
-e OVERRIDE_OPS=true \
-e EULA=TRUE \
-e MEMORY=3G \
--name minecraftserver \
docker.io/itzg/minecraft-bedrock-server:latest
```

Start with the reported docker run invocation and the container log showing fork/exec failure for /opt/bedrock-entry.sh. Inspect how bedrock-entry.sh is installed and executed in the container; done means the container starts without the operation-not-permitted error on the reported Docker and Ubuntu setup.

Written by the indexing model from the issue text.