Update quick start guide & learning-code-examples to reference 0.15 instead of 0.14 (#1916)

Co-authored-by: Carter Anderson <[email protected]>

Author: fallible-algebra

content/learn/quick-start/getting-started/_index.md

@@ -40,7 +40,7 @@ You can also speed up compile times by following the ["fast compiles"] section.
     # use the latest Bevy release
     git checkout latest
     # or a specific version
-    git checkout v0.14.0
+    git checkout v0.15.0
     ```
 
 4. Try the examples in the [examples folder](https://github.com/bevyengine/bevy/tree/latest/examples#examples)
@@ -63,7 +63,7 @@ Alternatively, you can manually add it to your project's Cargo.toml like this:
 
 ```toml
 [dependencies]
-bevy = "0.14" # make sure this is the latest version
+bevy = "0.15" # make sure this is the latest version
 ```
 
 Make sure to use the latest `bevy` crate version ([![Crates.io](https://img.shields.io/crates/v/bevy.svg)](https://crates.io/crates/bevy)).

content/learn/quick-start/getting-started/setup.md

@@ -124,7 +124,7 @@ cargo add bevy
   edition = "2021" # this needs to be 2021, or you need to set "resolver=2"
 
   [dependencies]
-  bevy = "0.14" # make sure this is the latest version
+  bevy = "0.15" # make sure this is the latest version
   ```
 </details>
 

learning-code-examples/Cargo.toml

@@ -5,7 +5,7 @@ publish = false
 autoexamples = false
 
 [dependencies]
-bevy = "0.14.0"
+bevy = "0.15.0"
 
 [lints]
 workspace = true