bump to 2.8.0 (#472)

Bump version to 2.8.0

Author: mtcarlone

README.md

@@ -47,7 +47,7 @@ See the generated [dbt docs site](https://brooklyn-data.github.io/dbt_artifacts/
 ```
 packages:
   - package: brooklyn-data/dbt_artifacts
-    version: 2.7.0
+    version: 2.8.0
 ```
 
 :construction_worker: Make sure to fix at least the **minor** version, to avoid issues when a new release is open. See the notes on upgrading below for more detail.

dbt_project.yml

@@ -1,5 +1,5 @@
 name: "dbt_artifacts"
-version: "2.7.0"
+version: "2.8.0"
 config-version: 2
 require-dbt-version: [">=1.3.0", "<1.10.0"]
 profile: "dbt_artifacts"