Fix: sorted IP addresses for servers.json (#574)

- Reduce deltas between updates
- Applies to the following providers
  - IPVanish
  - IVPN
  - Surfshark
  - Torguard
  - VPNUnlimited

internal/updater/providers/ipvanish/resolve.go

@@ -24,6 +24,7 @@ func getResolveSettings(minServers int) (settings resolver.ParallelSettings) {
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 }

internal/updater/providers/ipvanish/resolve_test.go

@@ -44,6 +44,7 @@ func Test_resolveHosts(t *testing.T) {
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 	presolver.EXPECT().Resolve(ctx, hosts, expectedSettings).

internal/updater/providers/ivpn/resolve.go

@@ -24,6 +24,7 @@ func getResolveSettings(minServers int) (settings resolver.ParallelSettings) {
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 }

internal/updater/providers/ivpn/resolve_test.go

@@ -44,6 +44,7 @@ func Test_resolveHosts(t *testing.T) {
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 	presolver.EXPECT().Resolve(ctx, hosts, expectedSettings).

internal/updater/providers/surfshark/resolve.go

@@ -26,6 +26,7 @@ func resolveHosts(ctx context.Context, presolver resolver.Parallel,
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 	return presolver.Resolve(ctx, hosts, settings)

internal/updater/providers/torguard/resolve.go

@@ -26,6 +26,7 @@ func resolveHosts(ctx context.Context, presolver resolver.Parallel,
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 	return presolver.Resolve(ctx, hosts, settings)

internal/updater/providers/vpnunlimited/resolve.go

@@ -26,6 +26,7 @@ func resolveHosts(ctx context.Context, presolver resolver.Parallel,
 			BetweenDuration: betweenDuration,
 			MaxNoNew:        maxNoNew,
 			MaxFails:        maxFails,
+			SortIPs:         true,
 		},
 	}
 	return presolver.Resolve(ctx, hosts, settings)