Fix links still pointing to spec repo main branch (open-telemetry#556)

docs/faas/aws-lambda.md

@@ -66,7 +66,7 @@ contain an incomplete trace context which indicates X-Ray isn’t enabled. The e
 `Context` will be valid and sampled only if AWS X-Ray has been enabled for the Lambda function. A user can
 disable AWS X-Ray for the function if the X-Ray Span Link is not desired.
 
-**Note**: When instrumenting a Java AWS Lambda, instrumentation SHOULD first try to parse an OpenTelemetry `Context` out of the system property `com.amazonaws.xray.traceHeader` using the [AWS X-Ray Propagator](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/context/api-propagators.md) before checking and attempting to parse the environment variable above.
+**Note**: When instrumenting a Java AWS Lambda, instrumentation SHOULD first try to parse an OpenTelemetry `Context` out of the system property `com.amazonaws.xray.traceHeader` using the [AWS X-Ray Propagator](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/context/api-propagators.md) before checking and attempting to parse the environment variable above.
 
 [Span Link]: https://opentelemetry.io/docs/concepts/signals/traces/#span-links
 

docs/messaging/messaging-spans.md

@@ -211,7 +211,7 @@ The following operations related to messages are defined for these semantic conv
 
 ### Span kind
 
-[Span kinds](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#spankind)
+[Span kinds](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/trace/api.md#spankind)
 SHOULD be set according to the following table, based on the operation a span describes.
 
 | Operation name | Span kind|
@@ -222,7 +222,7 @@ SHOULD be set according to the following table, based on the operation a span de
 | `deliver`      | `CONSUMER` |
 
 For cases not covered by the table above, the span kind should be set according
-to the [generic specification about span kinds](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#spankind),
+to the [generic specification about span kinds](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/trace/api.md#spankind),
 e. g. it should be set to CLIENT for the "Publish" span if its context is not
 used as creation context and if the "Publish" span models a synchronous call to
 the intermediary.