update Google tag ID for Google Analytics

Done manually with:
```
find . -iname "*.html" | xargs sed -i '' 's/UA-7301842-14/G-56KD6L3MDX/'
```

Future releases are expected to have the new tag ID due to changes in CXX-2975

categories/index.html

@@ -698,13 +698,13 @@ <h1> Categories </h1>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

index.html

@@ -698,13 +698,13 @@ <h1 id="mongodb-c-driver">MongoDB C++ Driver</h1>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/breaking-changes/index.html

@@ -849,13 +849,13 @@ <h1 id="improvements">Improvements</h1>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/configuration/index.html

@@ -885,13 +885,13 @@ <h2 id="caveats">Caveats</h2>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/index.html

@@ -746,13 +746,13 @@ <h1> The Legacy C&#43;&#43; Driver </h1>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/installation/index.html

@@ -974,13 +974,13 @@ <h5 id="linking-with-the-static-client-library">Linking with the static client l
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/tutorial/index.html

@@ -895,13 +895,13 @@ <h3 id="further-reading">Further Reading</h3>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>
 
 

legacy-v1/working-with-bson/index.html

@@ -734,13 +734,13 @@ <h3 id="bson-helper-functions">BSON Helper Functions</h3>
 </script>
 
 
-<script async src="https://www.googletagmanager.com/gtag/js?id=UA-7301842-14"></script>
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-56KD6L3MDX"></script>
 <script>
   window.dataLayer = window.dataLayer || [];
   function gtag(){dataLayer.push(arguments);}
   gtag('js', new Date());
 
-  gtag('config', 'UA-7301842-14');
+  gtag('config', 'G-56KD6L3MDX');
 </script>