Update IPLocationService type, add 51Degrees support (#25)

Author: postindustria-code

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
       - name: Cache dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/go/pkg/mod
           key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}

adcom1/ip_location_service.go

@@ -1,12 +1,14 @@
 package adcom1
 
 // IPLocationService represents services and/or vendors used for resolving IP addresses to geolocations.
-type IPLocationService int8
+type IPLocationService int16
 
 // Services and/or vendors used for resolving IP addresses to geolocations.
 const (
-	LocationServiceIP2Location IPLocationService = 1 // ip2location
-	LocationServiceNeustar     IPLocationService = 2 // Neustar (Quova)
-	LocationServiceMaxMind     IPLocationService = 3 // MaxMind
-	LocationServiceNetAcuity   IPLocationService = 4 // NetAcuity (Digital Element)
+	LocationServiceIP2Location               IPLocationService = 1   // ip2location
+	LocationServiceNeustar                   IPLocationService = 2   // Neustar (Quova)
+	LocationServiceMaxMind                   IPLocationService = 3   // MaxMind
+	LocationServiceNetAcuity                 IPLocationService = 4   // NetAcuity (Digital Element)
+	LocationService51DegreesHighConfidence   IPLocationService = 511 // 51Degrees (High Confidence)
+	LocationService51DegreesMediumConfidence IPLocationService = 512 // 51Degrees (Medium Confidence)
 )