Update golang Docker tag to v1.26 (#3372)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| golang | final | minor | `1.25` → `1.26` |
| golang | final | minor | `1.25-alpine` → `1.26-alpine` |

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e2e/Dockerfile

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
 # SPDX-License-Identifier: MIT
 
-FROM golang:1.25-alpine
+FROM golang:1.26-alpine
 
 RUN apk add --no-cache \
   chromium \

examples/pion-to-pion/answer/Dockerfile

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
 # SPDX-License-Identifier: MIT
 
-FROM golang:1.25
+FROM golang:1.26
 
 RUN go install github.com/pion/webrtc/v4/examples/pion-to-pion/answer@latest
 

examples/pion-to-pion/offer/Dockerfile

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
 # SPDX-License-Identifier: MIT
 
-FROM golang:1.25
+FROM golang:1.26
 
 RUN go install github.com/pion/webrtc/v4/examples/pion-to-pion/offer@latest