fix(docs): Add note in README mentioning tech discontinuity with previous version (#690)

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md
See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md
Co-authored-by: Benjamin E. Coe <[email protected]>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: 3 people

packages/google-cloud-compute/.readme-partials.yaml

@@ -0,0 +1,13 @@
+introduction: |-
+    > Node.js idiomatic client for [Compute Engine][product-docs].
+    [Compute Engine](https://cloud.google.com/compute/docs) is a
+    computing and hosting service that lets you create and run virtual
+    machines on Google infrastructure. Compute Engine offers scale,
+    performance, and value that lets you easily launch large compute
+    clusters on Google's infrastructure. There are no upfront
+    investments, and you can run thousands of virtual CPUs on a system
+    that offers quick, consistent performance.
+
+    This library is GA from version 3.1.0. It is
+    backwards-incompatible with prior versions 0.x.y, 1.x.y, 2.x.y,
+    and 3.0.y.

packages/google-cloud-compute/README.md

@@ -10,7 +10,18 @@
 
 
 
-Google Compute Engine Client Library for Node.js
+> Node.js idiomatic client for [Compute Engine][product-docs].
+[Compute Engine](https://cloud.google.com/compute/docs) is a
+computing and hosting service that lets you create and run virtual
+machines on Google infrastructure. Compute Engine offers scale,
+performance, and value that lets you easily launch large compute
+clusters on Google's infrastructure. There are no upfront
+investments, and you can run thousands of virtual CPUs on a system
+that offers quick, consistent performance.
+
+This library is GA from version 3.1.0. It is
+backwards-incompatible with prior versions 0.x.y, 1.x.y, 2.x.y,
+and 3.0.y.
 
 
 A comprehensive list of changes in each version may be found in

packages/google-cloud-compute/samples/README.md

@@ -6,7 +6,18 @@
 
 [![Open in Cloud Shell][shell_img]][shell_link]
 
-
+> Node.js idiomatic client for [Compute Engine][product-docs].
+[Compute Engine](https://cloud.google.com/compute/docs) is a
+computing and hosting service that lets you create and run virtual
+machines on Google infrastructure. Compute Engine offers scale,
+performance, and value that lets you easily launch large compute
+clusters on Google's infrastructure. There are no upfront
+investments, and you can run thousands of virtual CPUs on a system
+that offers quick, consistent performance.
+
+This library is GA from version 3.1.0. It is
+backwards-incompatible with prior versions 0.x.y, 1.x.y, 2.x.y,
+and 3.0.y.
 
 ## Table of Contents