ci: disable base64 line-wrapping when building gh-pages push auth header

The new stateless GITHUB_TOKEN format (~520 chars, rolled out from
April 27, 2026) makes the encoded AUTHORIZATION header exceed base64's
default 76-column wrap, embedding newlines that corrupt the header and
fail the push with 'Failed sending HTTP request'.

Assisted-by: Claude Code:claude-fable-5
Signed-off-by: Mikaël Barbero <mikael.barbero@eclipse-foundation.org>

Author: mbarbero

.github/workflows/site.yml

@@ -181,6 +181,6 @@ jobs:
             git commit -m "chore: update site for ${GITHUB_REF_NAME}"
             git remote set-url origin "https://github.com/${GITHUB_REPOSITORY}.git" 2>/dev/null \
               || git remote add origin "https://github.com/${GITHUB_REPOSITORY}.git"
-            auth_header=$(printf "x-access-token:%s" "${GITHUB_TOKEN}" | base64)
+            auth_header=$(printf "x-access-token:%s" "${GITHUB_TOKEN}" | base64 -w0)
             git -c "http.https://github.com/.extraheader=AUTHORIZATION: basic ${auth_header}" push origin gh-pages
           fi