fix(rnsdk) specify the RN version we support

Our SDK is only really tested with a single RN version, make sure to put
that in peerDependencies.

In addition, drop the peer dependency on @react-native/metro-config
since our project doesn't use it directly.

react-native-sdk/package.json

     "peerDependencies": {
         "@amplitude/react-native": "0.0.0",
         "@giphy/react-native-sdk": "0.0.0",
-        "@react-native/metro-config": "*",
         "@react-native-async-storage/async-storage": "0.0.0",
         "@react-native-clipboard/clipboard": "0.0.0",
         "@react-native-community/netinfo": "0.0.0",

react-native-sdk/update_sdk_dependencies.js

 const fs = require('fs');
+const semver = require('semver');
 
 const packageJSON = require('../package.json');
 
 const SDKPackageJSON = require('./package.json');
 
+// Skip checking these.
+const skipDeps = [ 'react', 'react-native' ];
+
 /**
  * Merges the dependency versions from the root package.json with the dependencies of the SDK package.json.
  */
 
     // Updates SDK peer dependencies.
     for (const key in packageJSON.dependencies) {
-        if (SDKPackageJSON.peerDependencies.hasOwnProperty(key)) {
-
-            // Updates all peer dependencies except react and react-native.
-            if (key !== 'react' && key !== 'react-native') {
-                SDKPackageJSON.peerDependencies[key] = packageJSON.dependencies[key];
-            }
+        if (SDKPackageJSON.peerDependencies.hasOwnProperty(key) && !skipDeps.includes(key)) {
+            SDKPackageJSON.peerDependencies[key] = packageJSON.dependencies[key];
         }
     }
 
+    // Set RN peer dependency.
+    const rnVersion = semver.parse(packageJSON.dependencies['react-native']);
+
+    if (!rnVersion) {
+        throw new Error('failed to parse React Native version');
+    }
+
+    // In RN the "major" version is the Semver minor.
+    SDKPackageJSON.peerDependencies['react-native'] = `~0.${rnVersion.minor}.0`;
+
     // Updates SDK overrides dependencies.
     for (const key in packageJSON.overrides) {
         if (SDKPackageJSON.overrides.hasOwnProperty(key)) {