docs: fix broken links in CHANGELOG

Fixes #4465.

Addresses the five 404s reported by the check-links workflow:

- pull/1670 entry: remove stray bracket and leading paren so the
  markdown link parses correctly.
- aws/ecs.md: point to the current location in the semantic-conventions
  repo. Semantic conventions moved out of opentelemetry-specification.
- v1.12.0rc2-0.32b0 release tag: the published tag on
  opentelemetry-python is v1.12.0rc2, not v1.12.0rc2-0.32b0.
- pull/227 entry: drop stray bracket inside the URL.
- #1033 link: restore missing slash between the org and repo.

Author: akerem16

CHANGELOG.md

@@ -1169,15 +1169,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Support `aio_pika` 9.x (([#1670](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1670])
+- Support `aio_pika` 9.x ([#1670](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1670))
 - `opentelemetry-instrumentation-redis` Add `sanitize_query` config option to allow query sanitization. ([#1572](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1572))
 - `opentelemetry-instrumentation-elasticsearch` Add optional db.statement query sanitization.
   ([#1598](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1598))
 - `opentelemetry-instrumentation-celery` Record exceptions as events on the span.
   ([#1573](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1573))
 - Add metric instrumentation for urllib
   ([#1553](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1553))
-- `opentelemetry/sdk/extension/aws` Implement [`aws.ecs.*`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md) and [`aws.logs.*`](https://opentelemetry.io/docs/reference/specification/resource/semantic_conventions/cloud_provider/aws/logs/) resource attributes in the `AwsEcsResourceDetector` detector when the ECS Metadata v4 is available
+- `opentelemetry/sdk/extension/aws` Implement [`aws.ecs.*`](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/resource/cloud-provider/aws/ecs.md) and [`aws.logs.*`](https://opentelemetry.io/docs/reference/specification/resource/semantic_conventions/cloud_provider/aws/logs/) resource attributes in the `AwsEcsResourceDetector` detector when the ECS Metadata v4 is available
   ([#1212](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1212))
 - `opentelemetry-instrumentation-aio-pika` Support `aio_pika` 8.x
   ([#1481](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1481))
@@ -1373,7 +1373,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add a test for asgi using NoOpTracerProvider
   ([#1367](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1367))
 
-## [1.12.0rc2-0.32b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.12.0rc2-0.32b0) - 2022-07-01
+## [1.12.0rc2-0.32b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.12.0rc2) - 2022-07-01
 
 - Pyramid: Only categorize 500s server exceptions as errors
   ([#1037](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/1037))
@@ -2007,7 +2007,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `opentelemetry-instrumentation-grpc` Add tests for grpc span attributes, grpc `abort()` conditions
   ([#236](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/236))
 - Add README and example app for Prometheus Remote Write Exporter
-  ([#227](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/227]))
+  ([#227](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/227))
 - `opentelemetry-instrumentation-botocore` Adds a field to report the number of retries it take to complete an API call
   ([#275](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/275))
 - `opentelemetry-instrumentation-requests` Use instanceof to check if responses are valid Response objects
@@ -2395,7 +2395,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `Added support for PyPy3` Initial release
 
-## [#1033](https://github.com/open-telemetryopentelemetry-python-contrib/issues/1033)
+## [#1033](https://github.com/open-telemetry/opentelemetry-python-contrib/issues/1033)
 
 ## Version 0.1a0 (2019-09-30)