Fix problem seen where flatterer 0.18.0 does not exist any more.

#537

Similiar to
b37d9b0

Extra packages: We aren't sure why pip-compile added these extra packages.

requirements.txt

@@ -2,7 +2,7 @@
 # This file is autogenerated by pip-compile with Python 3.9
 # by the following command:
 #
-#    pip-compile --resolver=backtracking requirements.in
+#    pip-compile requirements.in
 #
 alabaster==0.7.13
     # via sphinx
@@ -41,7 +41,7 @@ docutils==0.17.1
     #   sphinxcontrib-opendataservices-jsonschema
 erd-from-json-table-schema==0.2.0
     # via -r requirements.in
-flatterer==0.18.0
+flatterer==0.18.2
     # via hsds-schema-tools
 fqdn==1.5.1
     # via jsonschema
@@ -55,12 +55,16 @@ ijson==3.2.0.post0
     # via flatterer
 imagesize==1.4.1
     # via sphinx
+importlib-metadata==8.6.1
+    # via sphinx
 isoduration==20.11.0
     # via jsonschema
 jinja2==3.1.2
     # via
     #   myst-parser
     #   sphinx
+json-merge-patch==0.2
+    # via hsds-schema-tools
 jsonpointer==2.3
     # via
     #   jsonschema
@@ -124,13 +128,16 @@ pyyaml==6.0
 requests==2.31.0
     # via
     #   check-jsonschema
+    #   hsds-schema-tools
     #   sphinx
 rfc3339-validator==0.1.4
     # via jsonschema
 rfc3987==1.3.8
     # via jsonschema
 ruamel-yaml==0.17.21
     # via check-jsonschema
+ruamel-yaml-clib==0.2.12
+    # via ruamel-yaml
 six==1.16.0
     # via
     #   python-dateutil
@@ -194,6 +201,8 @@ urllib3==1.26.15
     #   transifex-client
 webcolors==1.13
     # via jsonschema
+zipp==3.21.0
+    # via importlib-metadata
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools