chore: add monthly Dependabot and harden checkout (#2713)

## What this changes
This PR adds Dependabot configuration and hardens GitHub Actions
checkout behavior.

## Dependabot
- adds .github/dependabot.yml
- enables grouped dependency updates
- schedules updates monthly
- configures a 7-day cooldown to avoid rapid follow-up bumps
- includes GitHub Actions updates

Configured update scopes:
- pip in /
- github-actions in /

## GitHub Actions hardening
Sets persist-credentials: false for ctions/checkout@v4 in:
- .github/workflows/windows_exe.yml
- .github/workflows/packages.yml
- .github/workflows/lint.yml
- .github/workflows/documentation.yml

## Why
- grouped updates reduce PR noise
- monthly cadence is lower maintenance
- cooldown helps avoid update churn
- disabling persisted checkout credentials follows least-privilege CI
practices

---------

Co-authored-by: Alexander Graf <17130992+aandergr@users.noreply.github.com>

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+  - package-ecosystem: pip
+    directory: "/"
+    schedule:
+      interval: monthly
+    cooldown:
+      default-days: 7
+
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: monthly
+    cooldown:
+      default-days: 7

.github/workflows/documentation.yml

@@ -8,11 +8,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: "Checkout Instaloader Repository"
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           fetch-depth: 0  # needed for building docs
+          persist-credentials: false
       - name: "Setup Python"
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: 3.14
           cache: 'pipenv'

.github/workflows/lint.yml

@@ -12,9 +12,11 @@ jobs:
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
       - name: Checkout Instaloader Repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
+        with:
+          persist-credentials: false
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
           cache: 'pipenv'

.github/workflows/packages.yml

@@ -11,9 +11,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: "Checkout Repository"
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
+        with:
+          persist-credentials: false
       - name: "Setup Python"
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: 3.14
       - name: "Get the tagged version"

.github/workflows/stale.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     
     steps:
-    - uses: actions/stale@v9
+    - uses: actions/stale@v10
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         only-labels: 'question'
@@ -21,7 +21,7 @@ jobs:
         days-before-stale: 21
         days-before-close: -1
         remove-stale-when-updated: false
-    - uses: actions/stale@v9
+    - uses: actions/stale@v10
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         stale-issue-message: 'There has been no activity on this issue for an extended period of time. This issue will be closed after further 14 days of inactivity.'

.github/workflows/windows_exe.yml

@@ -8,9 +8,11 @@ jobs:
     runs-on: windows-latest
     steps:
       - name: Checkout Instaloader repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
+        with:
+          persist-credentials: false
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.14"
           cache: 'pipenv'
@@ -28,7 +30,7 @@ jobs:
       - name: Create draft release and upload EXE as release asset
         if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v')
         id: create_release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v3
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:

docs/README.md

@@ -7,9 +7,10 @@ https://instaloader.github.io/
 
 ## Build
 
-The documentation is created with [Sphinx](http://www.sphinx-doc.org/). To build it, use
+The documentation is created with [Sphinx](http://www.sphinx-doc.org/). To build it, use (in the top-level directory
+of the Instaloader source tree):
 
 ```
-pip3 install -r requirements.txt
-make html
+pipenv sync --dev
+make -C docs html
 ```

docs/requirements.txt

@@ -1,2 +0,0 @@
-requests
-sphinx~=2.3