ci: use bootstrap.go for self-install in CI so bootstrapping also gets tested

Author: preminger

.github/workflows/checks.yml

@@ -95,7 +95,7 @@ jobs:
         run: brew bundle --no-upgrade --file=Brewfile
 
       - name: Self-install
-        run: go run main.go install
+        run: go run bootstrap.go
 
       - name: Parallelism check
         run: stave parallelismcheck

.github/workflows/release.yml

@@ -104,7 +104,7 @@ jobs:
         run: brew bundle --no-upgrade --file=Brewfile
 
       - name: Self-install
-        run: go run main.go install
+        run: go run bootstrap.go
 
       - name: Parallelism check
         run: stave parallelismcheck