ci: declare workflow-level contents: read on the 9 python-N.yml build workflows

Pins the default GITHUB_TOKEN to contents: read on the per-Python-
version build workflows. Each one runs sphinx-build / msgfmt against
the translated rst files and uploads the rendered HTML as a workflow
artifact - no GitHub API mutation.

- python-37.yml, python-38.yml, python-39.yml, python-310.yml,
  python-311.yml, python-312.yml, python-313.yml, python-314.yml,
  python-315.yml

update-tx-config.yml is intentionally left implicit; it commits and
pushes via GITHUB_TOKEN, so the scope is best declared by the
maintainer who owns the translation-sync flow.

Motivation: CVE-2025-30066 (March 2025 tj-actions/changed-files
compromise) exfiltrated GITHUB_TOKEN from workflow logs. Per-workflow
caps bound runtime authority irrespective of repo or org default,
give drift protection if the default ever widens, and are credited
per-file by the OpenSSF Scorecard Token-Permissions check.

YAML validated locally with yaml.safe_load.

Signed-off-by: Arpit Jain <arpitjain099@gmail.com>

Author: arpitjain099

.github/workflows/python-310.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "22 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-311.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "32 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-312.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "42 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-313.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "52 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-314.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "2 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-315.yml

@@ -8,6 +8,9 @@ on:
   schedule:
     - cron: "12 * * * *"
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-37.yml

@@ -2,6 +2,9 @@ name: python-37
 
 on: workflow_dispatch
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-38.yml

@@ -2,6 +2,9 @@ name: python-38
 
 on: workflow_dispatch
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-39.yml

@@ -3,6 +3,9 @@ name: python-39
 on:
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml