fix(plugins): fix rxjs 6 build errors

#2439

src/@ionic-native/plugins/blinkup/index.ts

@@ -1,5 +1,5 @@
 import { Plugin, Cordova, IonicNativePlugin } from '@ionic-native/core';
-import { Observable } from 'rxjs/Observable';
+import { Observable } from 'rxjs';
 import { Injectable } from '@angular/core';
 
 /**
@@ -70,7 +70,9 @@ export class BlinkUp extends IonicNativePlugin {
     callbackOrder: 'reverse',
     observable: true
   })
-  startBlinkUp(options: BlinkUpOptions): Observable<any> { return; }
+  startBlinkUp(options: BlinkUpOptions): Observable<any> {
+    return;
+  }
 
   /**
    * flashWifiBlinkUp - invokes the flash wifi process
@@ -81,7 +83,9 @@ export class BlinkUp extends IonicNativePlugin {
     callbackOrder: 'reverse',
     observable: true
   })
-  flashWifiBlinkUp(options: BlinkUpWifiOptions): Observable<any> { return; }
+  flashWifiBlinkUp(options: BlinkUpWifiOptions): Observable<any> {
+    return;
+  }
 
   /**
    * flashWPSBlinkUp - invokes the flash wps process
@@ -92,7 +96,9 @@ export class BlinkUp extends IonicNativePlugin {
     callbackOrder: 'reverse',
     observable: true
   })
-  flashWPSBlinkUp(options: BlinkUpWPSOptions): Observable<any> { return; }
+  flashWPSBlinkUp(options: BlinkUpWPSOptions): Observable<any> {
+    return;
+  }
 
   /**
    * abortBlinkUp - abort blinkup process
@@ -101,7 +107,9 @@ export class BlinkUp extends IonicNativePlugin {
   @Cordova({
     observable: true
   })
-  abortBlinkUp(): Observable<any> { return; }
+  abortBlinkUp(): Observable<any> {
+    return;
+  }
 
   /**
    * clearBlinkUpData - clear wifi data
@@ -110,5 +118,7 @@ export class BlinkUp extends IonicNativePlugin {
   @Cordova({
     observable: true
   })
-  clearBlinkUpData(): Observable<any> { return; }
+  clearBlinkUpData(): Observable<any> {
+    return;
+  }
 }