[chore] Prepare release v1.40.0/v0.134.0 (#13736)

Clone
#13735 to
pass the check for merge freeze.

---------

Signed-off-by: Bogdan Drutu <[email protected]>
Co-authored-by: otelbot <[email protected]>

Author: bogdandrutu

.chloggen/add-custom-encoder.yaml

@@ -58,6 +58,7 @@
       "Nanos",
       "OTELBOT",
       "OTEP",
+      "OTTL",
       "Olly",
       "Owais",
       "Paixão",

.chloggen/fix-map-copy.yaml

@@ -7,6 +7,14 @@ If you are looking for user-facing changes, check out [CHANGELOG.md](./CHANGELOG
 
 <!-- next version -->
 
+## v1.40.0/v0.134.0
+
+### 💡 Enhancements 💡
+
+- `exporterhelper`: Split exporterhelper into a separate module (#12985)
+
+<!-- previous-version -->
+
 ## v1.39.0/v0.133.0
 
 ### 🛑 Breaking changes 🛑

.chloggen/mx-psi_split-exporterhelper.yaml

@@ -7,6 +7,25 @@ If you are looking for developer-facing changes, check out [CHANGELOG-API.md](./
 
 <!-- next version -->
 
+## v1.40.0/v0.134.0
+
+### 💡 Enhancements 💡
+
+- `pdata`: Add custom grpc/encoding that replaces proto and calls into the custom marshal/unmarshal logic in pdata. (#13631)
+  This change should not affect other gRPC calls since it fallbacks to the default grpc/proto encoding if requests are not pdata/otlp requests.
+- `pdata`: Avoid copying the pcommon.Map when same origin (#13731)
+  This is a very large improvement if using OTTL with map functions since it will avoid a map copy.
+- `exporterhelper`: Respect `num_consumers` when batching and partitioning are enabled. (#13607)
+
+### 🧰 Bug fixes 🧰
+
+- `pdata`: Correctly parse OTLP payloads containing non-packed repeated primitive fields (#13727, #13730)
+  This bug prevented the Collector from ingesting most Histogram, ExponentialHistogram,
+  and Profile payloads.
+  
+
+<!-- previous-version -->
+
 ## v1.39.0/v0.133.0
 
 ### 🛑 Breaking changes 🛑

.chloggen/num_consumers_partitioner_enabled.yaml

@@ -4,8 +4,8 @@ go 1.24
 
 require (
 	github.com/stretchr/testify v1.10.0
-	go.opentelemetry.io/collector/consumer v1.39.0
-	go.opentelemetry.io/collector/pdata v1.39.0
+	go.opentelemetry.io/collector/consumer v1.40.0
+	go.opentelemetry.io/collector/pdata v1.40.0
 	go.uber.org/goleak v1.3.0
 )
 
@@ -17,7 +17,7 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	go.opentelemetry.io/collector/featuregate v1.39.0 // indirect
+	go.opentelemetry.io/collector/featuregate v1.40.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/sys v0.33.0 // indirect

.chloggen/pb-fix-unmarshal-unpacked.yaml

@@ -18,8 +18,8 @@ import (
 )
 
 const (
-	defaultBetaOtelColVersion   = "v0.133.0"
-	defaultStableOtelColVersion = "v1.39.0"
+	defaultBetaOtelColVersion   = "v0.134.0"
+	defaultStableOtelColVersion = "v1.40.0"
 )
 
 // errMissingGoMod indicates an empty gomod field