migration docs to css loader v1 (#25575)

* migration docs to css loader v1

* Update css-loader link to v1 in gatsby-plugin-sass

* Update css-loader link to v1 in gatsby-plugin-less

* Update css-loader link to v1 in gatsby-plugin-postcss

* Specifically note css-loader version in gatsby-plugin-sass

* Specifically note css-loader version in gatsby-plugin-postcss

* Specifically note css-loader version in gatsby-plugin-less

* chore: format

Co-authored-by: gatsbybot <mathews.kyle+gatsbybot@gmail.com>

docs/docs/migrating-from-v1-to-v2.md

@@ -676,7 +676,7 @@ If you use [`gatsby-plugin-typography`](/packages/gatsby-plugin-typography/), yo
 
 If you use CSS Modules and have class names with dashes in them, you'll need to change how you access the class names from JavaScript.
 
-This is because the [`camelCase` option](https://github.com/webpack-contrib/css-loader#camelcase) for CSS Modules has been changed from `false` to `dashesOnly`.
+This is because the [`camelCase` option](https://github.com/webpack-contrib/css-loader/tree/version-1#camelcase) for CSS Modules has been changed from `false` to `dashesOnly`.
 
 Here's an example with a class named `.my-class-name`:
 
@@ -692,7 +692,7 @@ export default function Component({ children }) (
 )
 ```
 
-The Gatsby v1 behavior can be restored by adjusting [CSS Loader options](https://github.com/webpack-contrib/css-loader#options).
+The Gatsby v1 behavior can be restored by adjusting [CSS Loader options](https://github.com/webpack-contrib/css-loader/tree/version-1#options).
 
 For vanilla CSS without a preprocessor:
 

packages/gatsby-plugin-less/README.md

@@ -37,7 +37,8 @@ plugins: [
 ]
 ```
 
-If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader)
+If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader/tree/version-1)
+**Note:** Gatsby is using `css-loader@1.0.1`.
 
 ```javascript
 // in gatsby-config.js

packages/gatsby-plugin-postcss/README.md

@@ -54,7 +54,8 @@ module.exports = () => ({
 })
 ```
 
-If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader)
+If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader/tree/version-1)
+**Note:** Gatsby is using `css-loader@1.0.1`.
 
 ```javascript
 // in gatsby-config.js

packages/gatsby-plugin-sass/README.md

@@ -46,7 +46,8 @@ plugins: [
 ]
 ```
 
-If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader):
+If you need to override the default options passed into [`css-loader`](https://github.com/webpack-contrib/css-loader/tree/version-1):
+**Note:** Gatsby is using `css-loader@1.0.1`.
 
 ```javascript:title=gatsby-config.js
 plugins: [