Update apidiff baseline to released version 1.40.0 (#421)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

Author: otelbot[bot]

docs/apidiffs/1.40.0_vs_1.39.0/opentelemetry-semconv.txt

@@ -0,0 +1,8 @@
+Comparing source compatibility of opentelemetry-semconv-1.40.0.jar against opentelemetry-semconv-1.39.0.jar
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.semconv.SchemaUrls  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) java.lang.String V1_40_0
+***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.semconv.ServiceAttributes  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) io.opentelemetry.api.common.AttributeKey<java.lang.String> SERVICE_INSTANCE_ID
+	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) io.opentelemetry.api.common.AttributeKey<java.lang.String> SERVICE_NAMESPACE

docs/apidiffs/current_vs_latest/opentelemetry-semconv.txt

@@ -1,8 +1,2 @@
-Comparing source compatibility of opentelemetry-semconv-1.40.0-SNAPSHOT.jar against opentelemetry-semconv-1.39.0.jar
-***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.semconv.SchemaUrls  (not serializable)
-	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
-	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) java.lang.String V1_40_0
-***  MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.semconv.ServiceAttributes  (not serializable)
-	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
-	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) io.opentelemetry.api.common.AttributeKey<java.lang.String> SERVICE_INSTANCE_ID
-	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) io.opentelemetry.api.common.AttributeKey<java.lang.String> SERVICE_NAMESPACE
+Comparing source compatibility of opentelemetry-semconv-1.40.0-SNAPSHOT.jar against opentelemetry-semconv-1.40.0.jar
+No changes.