feat: Bump version to v0.2.73 and update documentation

This commit updates the version number to v0.2.73 and makes corresponding changes in the README.md and Dockerfile.

Docker file install the default mode, this resolve many of installation issues.

Additionally, the installation instructions are updated to include support for different modes. Setup.py doesn't have anymore dependancy on Spacy.

The change log is also updated to reflect these changes.

Supporting websites need with-head browser.

crawl4ai/extraction_strategy.py

@@ -101,7 +101,7 @@ class LLMExtractionStrategy(ExtractionStrategy):
             prompt_with_variables = PROMPT_EXTRACT_BLOCKS_WITH_INSTRUCTION
             
         if self.extract_type == "schema":
-            variable_values["SCHEMA"] = json.dumps(self.schema)
+            variable_values["SCHEMA"] = json.dumps(self.schema, indent=2)
             prompt_with_variables = PROMPT_EXTRACT_SCHEMA_WITH_INSTRUCTION
 
         for variable in variable_values:
@@ -109,7 +109,7 @@ class LLMExtractionStrategy(ExtractionStrategy):
                 "{" + variable + "}", variable_values[variable]
             )
         
-        response = perform_completion_with_backoff(self.provider, prompt_with_variables, self.api_token)
+        response = perform_completion_with_backoff(self.provider, prompt_with_variables, self.api_token) # , json_response=self.extract_type == "schema")
         try:
             blocks = extract_xml_data(["blocks"], response.choices[0].message.content)['blocks']
             blocks = json.loads(blocks)
@@ -196,6 +196,10 @@ class LLMExtractionStrategy(ExtractionStrategy):
                 time.sleep(0.5)  # 500 ms delay between each processing
         else:
             # Parallel processing using ThreadPoolExecutor
+            # extract_func = partial(self.extract, url)
+            # for ix, section in enumerate(merged_sections):
+            #     extracted_content.append(extract_func(ix, section))            
+            
             with ThreadPoolExecutor(max_workers=4) as executor:
                 extract_func = partial(self.extract, url)
                 futures = [executor.submit(extract_func, ix, section) for ix, section in enumerate(merged_sections)]