20211116 volume-mounts - experimental branch - PR 3 of 3

[Paraphraser]

Under 2.x versions of docker-compose, volumes statements in service definitions that have trailing slashes cause:

Error response from daemon: invalid mount config for type "bind": bind source path does not exist:

This problem only shows up on first install of a container (ie when the container's persistent storage area has not yet been initialised).

There are 51 volumes statements across all current service definitions:

$ find ~/IOTstack/.templates -name "service.yml" -exec grep -H '\- \./volumes' {} \; | wc -l
51

Of those, 5 have a trailing "/" on either or both sides:

$ find ~/IOTstack/.templates -name "service.yml" -exec grep -H '\- \./volumes' {} \; | grep -e '/:' -e '/$'
/home/pi/IOTstack/.templates/telegraf/service.yml:    - ./volumes/telegraf/:/etc/telegraf
/home/pi/IOTstack/.templates/pihole/service.yml:      - ./volumes/pihole/etc-pihole/:/etc/pihole/
/home/pi/IOTstack/.templates/pihole/service.yml:      - ./volumes/pihole/etc-dnsmasq.d/:/etc/dnsmasq.d/
/home/pi/IOTstack/.templates/diyhue/service.yml:      - ./volumes/diyhue/:/opt/hue-emulator/export/
/home/pi/IOTstack/.templates/deconz/service.yml:    - ./volumes/deconz/:/opt/deCONZ

This pull request removes those extraneous trailing slashes. Changes do not affect current docker-compose or container behaviour.