add version specifiers for all dependencies (#427)

Author: dlqqq

pyproject.toml

@@ -30,15 +30,15 @@ classifiers = [
 ]
 dependencies = [
     "jupyter_server>=1.6,<3",
-    "traitlets",
-    "nbconvert",
+    "traitlets~=5.0",
+    "nbconvert~=7.0",
     "pydantic~=1.10",
-    "sqlalchemy<2",
-    "croniter",
-    "pytz",
-    "fsspec",
-    "s3fs",
-    "psutil"
+    "sqlalchemy~=1.0",
+    "croniter~=1.4",
+    "pytz==2023.3",
+    "fsspec==2023.6.0",
+    "s3fs==2023.6.0",
+    "psutil~=5.9"
 ]
 
 [project.optional-dependencies]