Add "onSwipedBegin" prop

[yotam-frid]

Hi! 👋

Firstly, thanks for your work on this project! It's a huge help and very convenient to work with.

Today I used patch-package to patch react-native-deck-swiper@2.0.12 for the project I'm working on.

I added a prop to allow invoking a callback before the swipe animation begins, in order to build a more responsive interface.

Here is the diff that solved my problem:

diff --git a/node_modules/react-native-deck-swiper/Swiper.js b/node_modules/react-native-deck-swiper/Swiper.js
index 1a657b3..16567cd 100644
--- a/node_modules/react-native-deck-swiper/Swiper.js
+++ b/node_modules/react-native-deck-swiper/Swiper.js
@@ -414,6 +414,7 @@ class Swiper extends Component {
     mustDecrementCardIndex = false
   ) => {
     this.setState({ panResponderLocked: true })
+    this.props.onSwipedBegin();
     this.animateStack()
     Animated.timing(this.state.pan, {
       toValue: {
@@ -974,6 +975,7 @@ Swiper.defaultProps = {
   marginBottom: 0,
   marginTop: 0,
   onSwiped: cardIndex => { },
+  onSwipedBegin: () => { },
   onSwipedAborted: () => { },
   onSwipedAll: () => { },
   onSwipedBottom: cardIndex => { },
diff --git a/node_modules/react-native-deck-swiper/index.d.ts b/node_modules/react-native-deck-swiper/index.d.ts
index 1ef616e..06879e9 100644
--- a/node_modules/react-native-deck-swiper/index.d.ts
+++ b/node_modules/react-native-deck-swiper/index.d.ts
@@ -32,6 +32,7 @@ declare module 'react-native-deck-swiper' {
     marginBottom?: number;
     marginTop?: number;
     onSwiped?: (cardIndex: number) => void;
+    onSwipedBegin: () => void;
     onSwipedAborted?: () => void;
     onSwipedAll?: () => void;
     onSwipedBottom?: (cardIndex: number) => void;

This issue body was partially generated by patch-package.