CI: Install bazel directly, forgo bazelisk (#157)

This brings it in line with the CI setup for the other Buildbarn
components, and reduces the setup complexity. We still use the same
source of truth as bazelisk so it still works well for developers.

Author: stagnation

.github/workflows/master.yaml

@@ -3,18 +3,6 @@
       "build_and_test": {
          "runs-on": "ubuntu-latest",
          "steps": [
-            {
-               "name": "Restore Bazelisk cache",
-               "uses": "actions/cache@v1",
-               "with": {
-                  "key": "bazelisk",
-                  "path": "~/.cache/bazelisk"
-               }
-            },
-            {
-               "name": "Installing Bazelisk",
-               "run": "bazelisk_fingerprint=231ec5ca8115e94c75a1f4fbada1a062b48822ca04f21f26e4cb1cd8973cd458 &&\n(echo \"${bazelisk_fingerprint} ${HOME}/.cache/bazelisk/bazel\" | sha256sum --check --quiet) || (\n  mkdir -p ~/.cache/bazelisk &&\n  curl -L https://github.com/bazelbuild/bazelisk/releases/download/v1.11.0/bazelisk-linux-amd64 > ~/.cache/bazelisk/bazelisk.tmp &&\n  chmod +x ~/.cache/bazelisk/bazelisk.tmp &&\n  mv ~/.cache/bazelisk/bazelisk.tmp ~/.cache/bazelisk/bazel\n) &&\n(echo \"${bazelisk_fingerprint} ${HOME}/.cache/bazelisk/bazel\" | sha256sum --check --quiet) &&\necho \"~/.cache/bazelisk\" >> ${GITHUB_PATH}\n"
-            },
             {
                "name": "Installing grpcurl",
                "run": "mkdir -p ~/.cache/grpcurl &&\ncurl -L https://github.com/fullstorydev/grpcurl/releases/download/v1.8.9/grpcurl_1.8.9_linux_x86_64.tar.gz | tar -xz -C ~/.cache/grpcurl &&\necho \"~/.cache/grpcurl\" >> ${GITHUB_PATH}\n"
@@ -27,6 +15,10 @@
                "name": "Check out source code",
                "uses": "actions/checkout@v1"
             },
+            {
+               "name": "Installing Bazel",
+               "run": "v=$(cat .bazelversion) && curl -L https://github.com/bazelbuild/bazel/releases/download/${v}/bazel-${v}-linux-x86_64 > ~/bazel && chmod +x ~/bazel && echo ~ >> ${GITHUB_PATH}"
+            },
             {
                "name": "Gazelle",
                "run": "bazel run //:gazelle"

.github/workflows/pull-requests.yaml

@@ -3,18 +3,6 @@
       "build_and_test": {
          "runs-on": "ubuntu-latest",
          "steps": [
-            {
-               "name": "Restore Bazelisk cache",
-               "uses": "actions/cache@v1",
-               "with": {
-                  "key": "bazelisk",
-                  "path": "~/.cache/bazelisk"
-               }
-            },
-            {
-               "name": "Installing Bazelisk",
-               "run": "bazelisk_fingerprint=231ec5ca8115e94c75a1f4fbada1a062b48822ca04f21f26e4cb1cd8973cd458 &&\n(echo \"${bazelisk_fingerprint} ${HOME}/.cache/bazelisk/bazel\" | sha256sum --check --quiet) || (\n  mkdir -p ~/.cache/bazelisk &&\n  curl -L https://github.com/bazelbuild/bazelisk/releases/download/v1.11.0/bazelisk-linux-amd64 > ~/.cache/bazelisk/bazelisk.tmp &&\n  chmod +x ~/.cache/bazelisk/bazelisk.tmp &&\n  mv ~/.cache/bazelisk/bazelisk.tmp ~/.cache/bazelisk/bazel\n) &&\n(echo \"${bazelisk_fingerprint} ${HOME}/.cache/bazelisk/bazel\" | sha256sum --check --quiet) &&\necho \"~/.cache/bazelisk\" >> ${GITHUB_PATH}\n"
-            },
             {
                "name": "Installing grpcurl",
                "run": "mkdir -p ~/.cache/grpcurl &&\ncurl -L https://github.com/fullstorydev/grpcurl/releases/download/v1.8.9/grpcurl_1.8.9_linux_x86_64.tar.gz | tar -xz -C ~/.cache/grpcurl &&\necho \"~/.cache/grpcurl\" >> ${GITHUB_PATH}\n"
@@ -27,6 +15,10 @@
                "name": "Check out source code",
                "uses": "actions/checkout@v1"
             },
+            {
+               "name": "Installing Bazel",
+               "run": "v=$(cat .bazelversion) && curl -L https://github.com/bazelbuild/bazel/releases/download/${v}/bazel-${v}-linux-x86_64 > ~/bazel && chmod +x ~/bazel && echo ~ >> ${GITHUB_PATH}"
+            },
             {
                "name": "Gazelle",
                "run": "bazel run //:gazelle"