Update the test vectors based on the changes made in zcash-test-vectors (#238)

QED-it/zcash-test-vectors#47 expands the sample set of Unicode code
points, which leads to a different random selection of asset description
strings, and therefore different asset base values in
`src/test_vectors/asset_base.rs`. This PR copies those changes in, along with 
some CI locking for tests to pass.

---------

Co-authored-by: Dmitry Demin <dmitry@qed-it.com>

Author: vivek-arte

.github/workflows/ci.yml

@@ -79,9 +79,11 @@ jobs:
       - name: Add target
         working-directory: ./ci-build
         run: rustup target add ${{ matrix.target }}
-      - name: Pin unicode-ident to version compatible with rustc 1.70
+      - name: Pin deps to versions compatible with rustc 1.70
         working-directory: ./ci-build
-        run: cargo update -p unicode-ident --precise 1.0.22
+        run: |
+          cargo update -p unicode-ident --precise 1.0.12
+          cargo update -p syn --precise 2.0.114
       - name: Build no_std for target
         working-directory: ./ci-build
         run: cargo build --verbose --target ${{ matrix.target }}

.github/workflows/lints-stable.yml

@@ -56,9 +56,11 @@ jobs:
       - name: Add target
         working-directory: ./ci-build
         run: rustup target add ${{ matrix.target }}
-      - name: Pin unicode-ident to version compatible with rustc 1.70
+      - name: Pin deps to versions compatible with rustc 1.70
         working-directory: ./ci-build
-        run: cargo update -p unicode-ident --precise 1.0.22
+        run: |
+          cargo update -p unicode-ident --precise 1.0.12
+          cargo update -p syn --precise 2.0.114
       - name: Clippy no_std for target
         working-directory: ./ci-build
         run: cargo clippy --verbose --target ${{ matrix.target }}