build: bump to 1.3.19 and update dependencies

- Raise the floors for pydantic, pydantic-settings, python-dotenv and
  isort to the releases they are tested against.
- Move the flit build backend to 4.x.

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["flit_core>=3.12.0,<4.0.0"]
+requires = ["flit_core>=4.0.2,<5.0.0"]
 build-backend = "flit_core.buildapi"
 
 [tool.flit.module]
@@ -7,7 +7,7 @@ name = "mdrsclient"
 
 [project]
 name = "mdrs-client-python"
-version = "1.3.18"
+version = "1.3.19"
 description = "The mdrs-client-python is python library and a command-line client for up- and downloading files to and from MDRS based repository."
 authors = [
     { name = "Yoshihiro OKUMURA", email = "yoshihiro.okumura@riken.jp" }
@@ -32,9 +32,9 @@ classifiers = [
 dependencies = [
     "requests>=2.34.2",
     "requests-toolbelt>=1.0.0",
-    "python-dotenv>=1.2.2",
-    "pydantic>=2.13.4",
-    "pydantic-settings>=2.14.2",
+    "python-dotenv>=1.2.3",
+    "pydantic>=2.13.5",
+    "pydantic-settings>=2.15.0",
     "PyJWT>=2.13.0",
     "validators>=0.35.0",
 ]
@@ -44,7 +44,7 @@ dev = [
     "black>=26.5.1",
     "flake8>=7.3.0",
     "Flake8-pyproject>=1.2.4",
-    "isort>=8.0.1",
+    "isort>=9.0.1",
     "pyright>=1.1.411",
 ]