Handle bug in Docker engine v23.0 update.

[veritas9872]

A bug in the Docker engine v23.0 update means that using the COPY command changes the directory permissions of the directory the file is copied to. This causes an issue in the /tmp directory. which requires write permissions for apt installation, etc.
The simplest method of solving this problem is to COPY the files to /opt instead of /tmp.

[veritas9872]

Also, add comments somewhere that the reason for using COPY instead of opening a binding to get the requirements files is to prevent cache misses when other files in the same directory are changed even if the target file is the same. This should be tested to see if the issue still occurs.

[veritas9872]

For example, is the apt stage reinstalled when pip or conda requirements are modified?

[veritas9872]

The cache missing is indeed an issue. If a directory is used as a bind mount, changing any file in that directory will cause a cache miss.

[veritas9872]

Apparently, the new behavior of v23.0 is not a bug but fixes previous undefined behavior. It will have to be fixed all the same.

[veritas9872]

See here moby/buildkit#3602

[veritas9872]

Checked that the updated version functions correctly in Docker engine v23.0.