chore(deps): Update litellm requirement from >=1.86.2 to >=1.91.0

Updates the requirements on [litellm](https://github.com/BerriAI/litellm) to permit the latest version.
- [Release notes](https://github.com/BerriAI/litellm/releases)
- [Commits](https://github.com/BerriAI/litellm/compare/v1.86.2...v1.91.0)

---
updated-dependencies:
- dependency-name: litellm
  dependency-version: 1.91.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: actions/setup-python@v7
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.10"
           cache: "pip"

.github/workflows/docs.yml

@@ -28,7 +28,7 @@ jobs:
       uses: actions/checkout@v6
 
     - name: Set up Python
-      uses: actions/setup-python@v7
+      uses: actions/setup-python@v6
       with:
         python-version: "3.10"
 

.github/workflows/lint.yml

@@ -19,7 +19,7 @@ jobs:
       uses: actions/checkout@v6
 
     - name: Set up Python
-      uses: actions/setup-python@v7
+      uses: actions/setup-python@v6
       with:
         python-version: "3.10"
 

.github/workflows/scheduled-tests.yml

@@ -21,7 +21,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: actions/setup-python@v7
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
           cache: "pip"
@@ -51,7 +51,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - uses: actions/setup-python@v7
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.10"
           cache: "pip"

.github/workflows/security.yml

@@ -22,7 +22,7 @@ jobs:
       uses: actions/checkout@v6
 
     - name: Set up Python
-      uses: actions/setup-python@v7
+      uses: actions/setup-python@v6
       with:
         python-version: "3.10"
 

requirements.txt

@@ -9,7 +9,7 @@ psutil
 fire
 fuzzywuzzy
 openai
-litellm>=1.86.2  # to support `from litellm import get_valid_models`
+litellm>=1.91.0  # to support `from litellm import get_valid_models`
 aiohttp>=3.14.0  # CVE-2026-22815, CVE-2026-34515, CVE-2026-34516, CVE-2026-34525; >=3.13.4 due to litellm==1.83.14 exact pin
 azure.identity
 pyarrow