Use private GitHub Actions runners

.github/workflows/cspell.yml

@@ -2,7 +2,7 @@ name: Spell Checking
 on: [push]
 jobs:
   cspell:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v2-beta

.github/workflows/eslint.yml

@@ -2,7 +2,7 @@ name: Linting
 on: [push]
 jobs:
   eslint:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v2-beta

.github/workflows/jest.yml

@@ -2,7 +2,7 @@ name: Jest
 on: [push]
 jobs:
   jest:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v2-beta

.github/workflows/label_audit.yml

@@ -2,7 +2,7 @@ name: Label Audit
 on: [push]
 jobs:
   labels:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-python@v1

.github/workflows/lockfile-lint.yml

@@ -2,7 +2,7 @@ name: Lockfile
 on: [push]
 jobs:
   lint:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v2-beta

.github/workflows/prettier.yml

@@ -2,7 +2,7 @@ name: Formatting
 on: [push]
 jobs:
   lint:
-    runs-on: ubuntu-latest
+    runs-on: SalesforceFoundation-ubuntu
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v2-beta