ubuntu-on-github: fix filename

Per contributors/contribute-docs/#file-names filename and anchor
should follow the title of the page.

Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>

Author: cpaelzer

docs/how-ubuntu-is-made/processes/index.md

@@ -90,5 +90,5 @@ Special review processes and quality safeguards for adding updates to published
 
 /SRU/stable-release-updates
 /MIR/main-inclusion-review
-github-ubuntu
+ubuntu-on-github
 ```

…buntu-is-made/processes/github-ubuntu.md …tu-is-made/processes/ubuntu-on-github.mddocs/how-ubuntu-is-made/processes/github-ubuntu.md renamed to docs/how-ubuntu-is-made/processes/ubuntu-on-github.md docs/how-ubuntu-is-made/processes/github-ubuntu.md renamed to docs/how-ubuntu-is-made/processes/ubuntu-on-github.md

@@ -1,4 +1,4 @@
-(github-ubuntu)=
+(ubuntu-on-github)=
 # Ubuntu on Github
 
 In addition to code/projects on Launchpad and the Ubuntu archive, Ubuntu also maintains projects under [github.com/ubuntu](https://github.com/ubuntu).
@@ -13,4 +13,4 @@ This is inclusive (Ubuntu Core Developers get access to the whole scope) and not
 
 ## Contributions
 
-Projects under [github.com/ubuntu](https://github.com/ubuntu) do not generally require the signing of the [Canonical contributor licence agreement](https://canonical.com/legal/contributors).
+Projects under [github.com/ubuntu](https://github.com/ubuntu) do not generally require the signing of the [Canonical contributor licence agreement](https://canonical.com/legal/contributors).