Upgrade to GitHub-native Dependabot (#203)

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

.dependabot/config.yaml

@@ -1,8 +0,0 @@
-version: 1
-update_configs:
-  - package_manager: "python"
-    directory: "/"
-    update_schedule: "monthly"
-  - package_manager: "docker"
-    directory: "/"
-    update_schedule: "monthly"

.github/dependabot.yml

@@ -0,0 +1,31 @@
+version: 2
+updates:
+- package-ecosystem: pip
+  directory: "/"
+  schedule:
+    interval: monthly
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: beautifulsoup4
+    versions:
+    - "> 4.8.1, < 4.9"
+  - dependency-name: google-cloud-datastore
+    versions:
+    - ">= 1.12.a, < 1.13"
+  - dependency-name: selenium
+    versions:
+    - "> 3.8.0"
+  - dependency-name: urllib3
+    versions:
+    - 1.26.2
+  - dependency-name: httpretty
+    versions:
+    - 1.0.3
+  - dependency-name: dnspython
+    versions:
+    - 2.0.0
+- package-ecosystem: docker
+  directory: "/"
+  schedule:
+    interval: monthly
+  open-pull-requests-limit: 10