Hello,

I am migrating CI from travis to actions and I am having problems using nvm.
looking at actions/virtual-environments Ubuntu1804-README 
nvm should be available, but when I run my action it errors with:

nvm: command not found

My action and script look like this:

workflow.yml:

jobs:
  test:
    runs-on: ubuntu-latest
steps:
  - name: Checkout
    uses: actions/checkout@v2

  - name: Build
    shell: bash -l -eo pipefail {0}
    run: .build.sh

.build.sh:

#!/bin/bash
set -eo pipefail
(re)source nvm if required
command -v nvm >/dev/null 2>&1 || {

if [[-s "${NVM_DIR}/nvm.sh"]]; then

source "${NVM_DIR}/nvm.sh"

elif [[-s "${HOME}/.nvm/nvm.sh"]]; then

source "${HOME}/.nvm/nvm.sh"

fi

}
nvm install 12.16.0

nvm use 12.16.0
yarn install --production=true --frozen-lockfile
yarn link

What am I doing wrong here, how do I use the image provided nvm in my script?

Edit:
After looking at the output of the ‘setup job’ step, I see that my action is being run against version 20200323.1  I should have noticed this sooner.

The version (as of making this edit [16 April 2020]) is old, there have been 3 tagged newer releases.
Is getting a version of the virtual envionment this far behind the current release expected?
Am I garanteed (per repo?) to get a consistent version when my action is run or maybe atleast no version older than X (I can see this leading to flakey action outcomes if I sometimes get a version with features and sometimes without)