fix: Allow Whitespace in CLI Variable Values

[Swivelgames]

Fixes #78
Fixes #75

• Linted
• Avoids Security Risks
• Simplifies regular expression for maintainability
• Allows for Whitespace, including new line characters in values (expected when paired with dotenv)
• Prevents illegal identifiers
• No new dependencies
• Tested/testable

Click here to review just the changes in this PR without the changes made by the linter.

Test Cases

Original Security Issue (Details Here):

node cli.js -v test="$(echo bax; echo foo=bar)" --debug

[ '.env' ]
{ test: 'bax\nfoo=bar' }

Complex Test:

node cli.js -v foo=bar=baz -v "pew=pew" -v NODE_OPTIONS='--no-experimental-fetch --trace-warnings --loader=ts-node/tsm --loader=esmock' --debug

[ '.env' ]
{
  foo: 'bar=baz',
  pew: 'pew',
  NODE_OPTIONS: '--no-experimental-fetch --trace-warnings --loader=ts-node/tsm --loader=esmock'
}

Other Tests

node cli.js -v NODE_OPTIONS=--no-experimental-fetch --debug

[ '.env' ]
{ NODE_OPTIONS: '--no-experimental-fetch' }

---

node cli.js -v NODE_OPTIONS=--loader=esmock --debug

[ '.env' ]
{ NODE_OPTIONS: '--loader=esmock' }

---

node cli.js -v NODE_OPTIONS='--no-experimental-fetch --trace-warnings' --debug

[ '.env' ]
{ NODE_OPTIONS: '--no-experimental-fetch --trace-warnings' }

---

node cli.js -v test1=foo --debug

[ '.env' ]
{ test1: 'foo' }

---

node cli.js -v test2='bar' --debug

[ '.env' ]
{ test2: 'bar' }

---

node cli.js -v test3="'baz'" --debug

[ '.env' ]
{ test3: "'baz'" }

---

node cli.js \
    -v foo=bar=baz \
    -v "pew=pew" \
    -v meow="mix" \
    -v "foos"="'ball'" \
    -v NODE_OPTIONS='
           --no-experimental-fetch
           --trace-warnings
           --loader=ts-node/tsm
           --loader=esmock
    ' \
    --debug

[ '.env' ]
{
  foo: 'bar=baz',
  pew: 'pew',
  meow: 'mix',
  foos: "'ball'",
  NODE_OPTIONS: '\n' +
    '           --no-experimental-fetch \n' +
    '           --trace-warnings \n' +
    '           --loader=ts-node/tsm \n' +
    '           --loader=esmock\n' +
    '    '
}

[entropitor]

Released as https://github.com/entropitor/dotenv-cli/releases/tag/v7.4.0

[psychobolt]

const value = process.env[argv.p]
  if (typeof value === 'string') {
    value = `\`${value}\``

This change throws a exception: TypeError: Assignment to constant variable.

[entropitor]

@psychobolt This has now been fixed in v7.4.1