.github/workflows: Don't run CI checks for markdown-only updates

Update the ci-prefixed workflows and ensure that CI isn't running when
only markdown files are updated.

Author: timflannagan

.github/workflows/build.yml

@@ -5,6 +5,7 @@ on:
     - '**'
     - '!doc/contributors/**'
     - '!doc/design/**'
+    - '**/*.md'
 jobs:
   image:
     runs-on: ubuntu-latest

.github/workflows/e2e-kind.yml

@@ -5,6 +5,7 @@ on:
     - '**'
     - '!doc/contributors/**'
     - '!doc/design/**'
+    - '**/*.md'
   schedule:
   - cron: '0 0 * * *' # daily to pick up releases
 jobs:

.github/workflows/e2e-minikube.yml

@@ -5,6 +5,7 @@ on:
     - '**'
     - '!doc/contributors/**'
     - '!doc/design/**'
+    - '**/*.md'
   schedule:
   - cron: '0 0 * * *' # daily to pick up releases
 jobs:

.github/workflows/e2e-tests.yml

@@ -7,6 +7,7 @@ on:
     paths:
       - '**'
       - '!doc/**'
+      - '**/*.md'
 jobs:
   e2e-tests:
     runs-on: ubuntu-latest

.github/workflows/unit.yml

@@ -7,6 +7,7 @@ on:
     paths:
       - '**'
       - '!doc/**'
+      - '**/*.md'
 jobs:
   unit:
     runs-on: ubuntu-latest

.github/workflows/verify.yml

@@ -7,6 +7,7 @@ on:
     paths:
       - '**'
       - '!doc/**'
+      - '**/*.md'
 jobs:
   verify:
     runs-on: ubuntu-latest