use actual nodejs versions for CI, fix dependabot file location

.github/dependabot.yml

@@ -4,3 +4,5 @@ updates:
     directory: '/'
     schedule:
       interval: 'daily'
+    ignore:
+      - dependency-name: 'typescript'

.github/workflows/build-test.yml

@@ -2,9 +2,9 @@ name: Build & Test
 
 on:
   push:
-    branches: [master]
+    branches: [main]
   pull_request:
-    branches: [master]
+    branches: [main]
 
 jobs:
   build:
@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [14.x, 15.x]
+        node-version: [16.x, 18.x]
 
     steps:
       - uses: actions/checkout@v2

dependabot.yml

@@ -1,8 +0,0 @@
-version: 2
-updates:
-  - package-ecosystem: 'npm'
-    directory: '/'
-    schedule:
-      interval: 'daily'
-    ignore:
-      - dependency-name: 'typescript'