Deprecate parse_headers function

Fixes open-telemetry#2376

opentelemetry-api/src/opentelemetry/util/re.py

@@ -12,12 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import logging
+from logging import getLogger
 from re import compile, split
 from typing import Dict, List, Mapping
 from urllib.parse import unquote
 
-_logger = logging.getLogger(__name__)
+from deprecated import deprecated
+
+_logger = getLogger(__name__)
 
 # The following regexes reference this spec: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md#specifying-headers-via-environment-variables
 
@@ -40,6 +42,13 @@
 
 
 # pylint: disable=invalid-name
+
+
+@deprecated(version="1.15.0", reason="You should use parse_env_headers")
+def parse_headers(s: str) -> Mapping[str, str]:
+    return parse_env_headers(s)
+
+
 def parse_env_headers(s: str) -> Mapping[str, str]:
     """
     Parse ``s``, which is a ``str`` instance containing HTTP headers encoded
@@ -57,7 +66,7 @@ def parse_env_headers(s: str) -> Mapping[str, str]:
             _logger.warning(
                 "Header format invalid! Header values in environment variables must be "
                 "URL encoded per the OpenTelemetry Protocol Exporter specification: %s",
-                header
+                header,
             )
             continue
         # value may contain any number of `=`