update dependencies, add dependabot (#70)

* update dependencies
* add some status badges
    crates.io
    testing status
    dependency status
* add cargo-audit ci
* add dependabot for cargo and github actions updates

.github/dependabot.yml

@@ -0,0 +1,26 @@
+---
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: daily
+      time: "10:00"
+      timezone: EST
+    open-pull-requests-limit: 10
+    commit-message:
+      prefix: chore
+      include: scope
+  - package-ecosystem: cargo
+    directory: /
+    schedule:
+      interval: daily
+      time: "06:00"
+      timezone: EST
+    open-pull-requests-limit: 10
+    allow:
+      # direct and indirect updates
+      - dependency-type: "all"
+    commit-message:
+      prefix: chore
+      include: scope

.github/workflows/cargo-audit.yml

@@ -0,0 +1,18 @@
+name: Cargo Audit Scanning
+on:
+  push:
+    paths:
+      - "**/Cargo.toml"
+      - "**/Cargo.lock"
+  schedule:
+    - cron: "0 14 * * *" # 14:00 UTC
+permissions:
+  repository-projects: read
+jobs:
+  cargo-audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions-rs/audit-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}