Minor cleanup: Node v12, Airbnb-base eslint

Changed:

• No new features

Under the hood:

• Now runs on Node v12 (LTS)
• Using airbnb-base eslint configuration
• Refreshed packages

Version: removed defunct console message

0.5.6

Index: removed defunct hardcoded version

Dockerfile: layer compression

Changes:

• Dockerfile: compressed layers into 1 for speed
• Freshened NPM packages from security audit

Security: updated vulnerable libraries

Merge pull request #26 from bryanlatten/npm-audit

Package: npm security audit

Index: safety loading passed policy file

Has been manually tested for:

• bad files
• unreadable files
• directories.

Further improvement: add dgoss testing to travis for automated validation

Dockerfile: using node 9, npm shrinkwrap

Changed:

Updated node version
Using new npm shrinkwrap instead of package lock

Default Policy: disallowing MSI explicit identity and agent fill

Changed:

• com.swipely.iam-docker.msi-explicit-identity is disallowed as a label in default policy
• AGENT_FILL is disallowed as an environment variable and label in default policy

Node: upgraded to 8.X engine

Changes:

• Node engine updated to 8.X, unlocked minor and patch versions

Layer Count: gate the number of FS layers

New:

• Use layers max, layers warning to enforce the number of filesystem layers a container may have

Updated:

• Port range default policy updated to max out at actual max port number

Flags: allow max, warning, port range, labels, and envs specified from CLI

 Checks a Docker image's properties against a policy

 Options:

   -h, --help             output usage information
   -V, --version          output the version number
   -p, --policy <file>    image policy, defaults to ./default_policy.conf
   -i, --inspect          docker inspect output (may also be specified as stdin)
   -m, --max <size>       image size max, in MB
   -w, --warning <size>   image size warning, in MB
   -l, --labels <labels>  add disallowed labels, comma-separated
   -e, --envs <keys>      add disallowed env keys, comma-separated
   -r, --range <ports>    low-high ports that are allowed```