chore(deps): bump idna from 3.10 to 3.15 in /.kokoro/docs/docker (#9197)

Bumps [idna](https://github.com/kjd/idna) from 3.10 to 3.15.
- [Release notes](https://github.com/kjd/idna/releases)
- [Changelog](https://github.com/kjd/idna/blob/master/HISTORY.md)
- [Commits](kjd/idna@v3.10...v3.15)

---
updated-dependencies:
- dependency-name: idna
  dependency-version: '3.15'
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.kokoro/docs/docker/requirements.txt

@@ -4,9 +4,9 @@
 #
 #    pip-compile --generate-hashes requirements.in
 #
-cachetools==7.1.1 \
-    --hash=sha256:0335cd7a0952d2b22327441fb0628139e234c565559eeb91a8a4ac7551c5353d \
-    --hash=sha256:27bdf856d68fd3c71c26c01b5edc312124ed427524d1ddb31aa2b7746fe20d4b
+cachetools==6.2.6 \
+    --hash=sha256:16c33e1f276b9a9c0b49ab5782d901e3ad3de0dd6da9bf9bcd29ac5672f2f9e6 \
+    --hash=sha256:8c9717235b3c651603fff0076db52d6acbfd1b338b8ed50256092f7ce9c85bda
     # via google-auth
 certifi==2026.1.4 \
     --hash=sha256:9943707519e4add1115f44c2bc244f782c0249876bf51b6599fee1ffbedd685c \
@@ -95,25 +95,27 @@ googleapis-common-protos==1.70.0 \
     --hash=sha256:0e1b44e0ea153e6594f9f394fef15193a68aaaea2d843f83e2742717ca753257 \
     --hash=sha256:b8bfcca8c25a2bb253e0e0b0adaf8c00773e5e6af6fd92397576680b807e0fd8
     # via google-api-core
-idna==3.10 \
-    --hash=sha256:12f65c9b470abda6dc35cf8e63cc574b1c52b11df2c86030af0ac09b01b13ea9 \
-    --hash=sha256:946d195a0d259cbba61165e88e65941f16e9b36ea6ddb97f00452bae8b1287d3
+idna==3.15 \
+    --hash=sha256:048adeaf8c2d788c40fee287673ccaa74c24ffd8dcf09ffa555a2fbb59f10ac8 \
+    --hash=sha256:ca962446ea538f7092a95e057da437618e886f4d349216d2b1e294abfdb65fdc
     # via requests
 proto-plus==1.26.1 \
     --hash=sha256:13285478c2dcf2abb829db158e1047e2f1e8d63a077d94263c2b88b043c75a66 \
     --hash=sha256:21a515a4c4c0088a773899e23c7bbade3d18f9c66c73edd4c7ee3816bc96a012
     # via
     #   -r requirements.in
     #   google-api-core
-protobuf==7.34.1 \
-    --hash=sha256:34b84ce27680df7cca9f231043ada0daa55d0c44a2ddfaa58ec1d0d89d8bf60a \
-    --hash=sha256:403b093a6e28a960372b44e5eb081775c9b056e816a8029c61231743d63f881a \
-    --hash=sha256:5185e0e948d07abe94bb76ec9b8416b604cfe5da6f871d67aad30cbf24c3110b \
-    --hash=sha256:8ff40ce8cd688f7265326b38d5a1bed9bfdf5e6723d49961432f83e21d5713e4 \
-    --hash=sha256:9ce42245e704cc5027be797c1db1eb93184d44d1cdd71811fb2d9b25ad541280 \
-    --hash=sha256:bb3812cd53aefea2b028ef42bd780f5b96407247f20c6ef7c679807e9d188f11 \
-    --hash=sha256:d8b2cc79c4d8f62b293ad9b11ec3aebce9af481fa73e64556969f7345ebf9fc7 \
-    --hash=sha256:e97b55646e6ce5cbb0954a8c28cd39a5869b59090dfaa7df4598a7fba869468c
+protobuf==6.33.6 \
+    --hash=sha256:0cd27b587afca21b7cfa59a74dcbd48a50f0a6400cfb59391340ad729d91d326 \
+    --hash=sha256:77179e006c476e69bf8e8ce866640091ec42e1beb80b213c3900006ecfba6901 \
+    --hash=sha256:7d29d9b65f8afef196f8334e80d6bc1d5d4adedb449971fefd3723824e6e77d3 \
+    --hash=sha256:9720e6961b251bde64edfdab7d500725a2af5280f3f4c87e57c0208376aa8c3a \
+    --hash=sha256:a6768d25248312c297558af96a9f9c929e8c4cee0659cb07e780731095f38135 \
+    --hash=sha256:bd56799fb262994b2c2faa1799693c95cc2e22c62f56fb43af311cae45d26f0e \
+    --hash=sha256:c96c37eec15086b79762ed265d59ab204dabc53056e3443e702d2681f4b39ce3 \
+    --hash=sha256:e2afbae9b8e1825e3529f88d514754e094278bb95eadc0e199751cdd9a2e82a2 \
+    --hash=sha256:e9db7e292e0ab79dd108d7f1a94fe31601ce1ee3f7b79e0692043423020b0593 \
+    --hash=sha256:f443a394af5ed23672bc6c486be138628fbe5c651ccbc536873d7da23d1868cf
     # via
     #   gcp-docuploader
     #   google-api-core